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Blue-footed boobies have webbed feet and are comically clumsy when they walk on land. Evolutionary scientists view these feet as

the outcome of a tradeoff: webbed feet perform poorly on land, but are very helpful in diving for food.

Which of the following statements would Darwin have disagreed with?

Descent with modification occurs through inheritance of acquired characteristics

Broccoli, cabbages, and Brussels sprouts all descend from the same wild mustard and can still interbreed. These varieties were produced by.

Artificial selection

Humans share several features with salamanders. Certain genes and proteins are nearly identical between the two species: both species have four limbs with a similar skeletal structure; the species vestigial tailbone. In evolutionary terms, these are examples of


Darwin was the first person to draw an evolutionary tree, a diagram that represents

evidence- based hypotheses regarding our understanding of patterns of evolutionary descent.

Which sentence best describes the true nature of natural selection?

Heritable traits that promote reproduction become more frequent in a population from one generation to the next.

An elk herd is observed over many generations. Most of the full-grown bull elk have antlers of nearly the same size. The average antler size remains constant over the generations. Which of the following effects probably accounts for the situation?

stabilizing selection

A women struggling with bacterial illness is prescribed a months supply of a potent antibiotic. She takes the antibiotic for about 2 weeks and feels much better. Should she save the remaining two week supply or should she continue taking the drug?

She should continue taking the drug until her immune system can completely eliminate the infection. Otherwise the remaining bacteria in her system may recover, and they will probably be resistant

The sickle-cell allele produces a serious blood disease in homozygotes. Why doesn't natural selection eliminate this allele from all human populations?

In populations were endemic malaria is present, heterozygotes have an important advantage: They are resistant to malaria and therefore are more likely to survive and produce offspring that carry the allele.

Frequency-dependent selection, as seen in the case of the scale-eating fish in lake Tanganyika, tends to

maintain two phenotypes in a dynamic equilibrium in a population

During which of the following stages of food processing is undigested material removed from the digestive tract


An alimentary canal is best defined as

a tube-shaped compartment for the transport, digestion, and absorption of food

Which of the following correctly lists the order of the parts of the human digestive system, from first to last contact with food matter?

oral cavity, pharynx, esophagus, stomach, small intestine, large intestine

Digestion begins in the

oral cavity

The mucous-producing cells that line the stomach

lubricate and protect the stomach lining

In the digestive system, most nutrient absorption occurs in the

small intestine

organisms suffering from malnutrition may have a diet deficient in

one or more essential nutrients

which of the following is a hormone produced by adipose cells that help to control appetite?


Animals that maintain internal body temperature using heat generated by their own metabolism are called


To enhance heat loss, humans sweat, an adaption known as

evaporative cooling

sweating commonly results in dehydration. Of the choices listed, which would be the best option for rehydration after intense exercise?

sports drink

mammals have evolved a sophisticated mechanism for eliminating nitrogenous wastes that involves

forming urea and storing it in concentrated solution

whats is the name of the functional unit of the kidneys


during production of urine, a major function of the kidney is

water conservation

what is the function of antidiurectic hormone?

to increase water reabsorption

when a salmon moves from the ocean to a freshwater environment, you would expect its urine volume to _______ and its rate of salt absorption to ______.


In a dialysis machine, wastes are removed from blood plasma by process of


through which of the following structures does urine leave the bladder?


increased brain size had many benefits for early humans. one example is

complex social structure with the ability to adapt to changing environments

when comparing the differences between human and chimpanzee DNA

the differences are generally found in the gene switches that determine when and how genes are expressed.

walking upright has both pros and cons. some of the pros of walking upright include

looking large to predators, the ability to harvest more food, the ability to carry young.

homo erectus was the first early human to spend most of its time walking upright


tool use is uniquely human


chimpanzees are humans closest living relatives


lower back pain can be attributed to walking upright, which formed the curvature at the base of the spine


Humans and chimpanzees have 90% identical genome sequences


Darwins ideas about evolution were formed after observing marine iguanas on the galapagos islands


____ genes are responsible for coding for self-proteins.


A molecule that can elicit an adaptive immune response is called

an antigen

Medullary breathing centers directly sense and respond to

blood pH and CO2 concentration

which part of the diagram shows the alveoli?

Part D

Air leaving human lung during exhalation contains

carbon dioxide and unused oxygen

during gas exchange, body cells

release CO2 and take in O2

As blood moves away from the heart towards the tissues, the relative size of blood vessels _____, the blood pressure ______, and the velocity of blood flow _______.


which of the following is a function of the nasal cavities in humans?

warming inhaled air

arteries are distinguished from veins based on all of the following features except

the amount of oxygen present in the blood

The main function of the AV node is to

relay a signal for the ventricles to contract

The maximum amount of air that a human can inhale and exhale is called the

vital capacity

Which of the following cell types is responsible for the cell-mediated immune response?

T cells

Natural Killer Cells

attack virus-infected cells by releasing chemicals that lead to the death of the cell

Oxygen moves from blood into the interstitial fluid and then to body cells because

it diffuses from a region of higher partial pressure to a region of lower partial pressure

which of the following distingueshes the secondary immune response from the primary?

The secondary response is faster and stronger

which of the following choices best describes a plasma cell?

It is a differentiated B cell

Oxygen-poor blood is carried from the heart of a mammal to the lungs via the

pulmonary arteries

What type of blood vessel is solely responsible for exchange between the blood and the interstitial fluid?


which of the following helps activate our nonspecific (innate) defense system?


A primary immune response is

the immune response elicited by the first exposure of lymphocytes to a particular antigen

cardiac output is defined as the volume of blood pumped by an ____ each time it contracts


Which of the following types of cells does HIV preferentially infect?

helper T cells

The reason animals need continuous supply of oxygen is

obtain energy from their food

after binding to an infected cell, the cytotoxic T cell

releases a protein called perforin

what part of the human brain contains the primary breathing control center?

medulla oblongata

multipotent stem cells found in the red marrow inside bones

can differentiate into all blood cells and platelets

An adult humans red blood cells are formed in the

bone marrow

which blood vessels have the thinnest walls


labored breathing, coughing, lung infections, and respiratory failure are characteristics defining

chronic obstructive pulmonary diseases

which of the following contributes to gas exchange in the human fetus

the stronger attraction that fetal hemoglobin has for oxygen when compared to adult hemoglobin

blood clots are formed by platelets and the plasma protein


which of the following statements about mammalian circulatory systems is false?

The left side of a mammals heart sends blood to the lungs

The liquid part of blood is called


what prompts a newborn baby to start to breather?

an increase in the concentration of oxygen in the baby's blood

which of the following options correctly lists the direction of carbon dioxide travel as it leaves the body?

alveoli, bronchioles, bronchi, trachea, larynx, pharynx

which of the following is a function of the circulatory system?

transporting nutrients to body cells

The oxygen-carrying component in red blood cells is


which of the following wander through the interstitial fluid and consume any bacteria and virus-infected cells they encounter?


anaphylactic shock is an example of an

allergic response

which of the following cells are phagocytes?

monocytes and neutrophils

which of the following can contribute to high blood pressure?


blood flow through capillaries is controlled by

precapillary sphincters and smooth muscle in the walls of arterioles

what type of immune response is always disadvantageous to a person?


which of the following cell types is responsible for the humoral immune response?

B cells

The human lymphatic system consists of all of the following structures except the


The basic function of the activated T cells is to battle

pathogens that have alreasy entered body cells

one kind of vaccine consists of

a harmless variant strain of a disease-causing microbe

cigarette smoke can affect the white blood cells that reside in our lungs, whose purpose is to

engulf foreign particles

which of the following animals requires the largest and most complex lungs proportional to its overall body size?


Plasma proteins are involved in all of the following activities except

carrying oxygen

The autonomic nervous system

regulates the internal environment of the body

The central communication conduit between the brain and the rest of the body is the

spinal cord

functionally, the muscle fibers fundamental unit for contraction is the


muscles are connected to the bones by


a tennis player serving the ball uses fast muscle fibers. The ATP needed to accomplish this would come from

anaerobic fermentation

The signal that crosses a synapse is stopped when

the neurotransmitter is enzymatically broken down or transported back to the signaling cell

Bone is composed of

living cells that secrete a surrounding matrix

the neurotransmitter found at the synapse between nerves and human skeletal muscle cells is


which division of the human nervous system carries signals to skeletal muscles?

motor system

action potentials normally travel along an axon

away from the cell body

According to the sliding filament model of muscle contraction, a sarcomere contracts when its

thin filaments slie towards each other across its thick filaments

skeletal muscles

work in antagonistic pairs

nervous system effector cells

include muscle cells and gland cells

which of the following statements regarding the brain is true

the blood-brain barrier helps to maintain a stable chemical environment for the brain

the gap between the transmitting and receiving neurons in a chemical synapse is known as the

synaptic cleft

The relationship between spinal nerves and the spinal cord is most like the relationship between

an interstate highway and the many roads that intersect with it via on- and off- ramps

which of the following structures constitutes part of the axial skeleton


The calcium that triggers muscle contraction is stored in

the endoplasmic reticulum

which of the following statements regarding exercise is true

the main source of energy during aerobic exercise is ATP from aerobic respiration

Osteoporosis is characterized by

low bone mass and structural deterioration of the bone tissue.

what part of the neuron carries signals toward the part of the cell that houses the nucleus


one neurotransmitter associated with sleep, mood, attention, and learning is


Muscles that are constantly active, such as those maintaining our body posture, having a high proportion of

slow, fatigue-resistant fibers.

Parkinsons disease is associated with a deficiency in


which of the following statements regarding the nervous system is true

motor neurons convey signals from the CNS to the effector cells

which of the following statements about resting potential is true

the sodium-potassium pump contributes to the resting membrane potential

changes occur within a sarcomere during muscle contraction. one change is that the

Z lines move closer together

The shoulder joint where the humerus meets the shoulder gridle is an example of

a ball and socket joint

a motor unit is

a motor neuron and all of the muscle fibers it controls

The speed of impulse conduction along an axon may be increase by

a myelin sheath

Neurotransmitters that open Na+ channels and trigger action potentials in receiving cells are called


The enteric division of the autonomic nervous system consists of neurons in the digestive tract, the gallbladder and

the pancreas

a thick filament consists of


which of the following statements about locomotion is true

locomotion requires animals to overcome friction and gravity

multiple sclerosis results from an autoimmune disease that primarily involves

destruction of the myelin sheath

which of the following statements best describes the power stroke of muscle contraction?

the myosin head bends, pulling the thin filament toward the center of the sarcomere

which part of a bone contains mostly stored fat?

yellow bone marrow

during transmission across a typical chemical synapse

neurotransmitter molecules bind to receptors in the receiving cells plasma membrane

the functional unit of the nervous system is the


in all vertebrates, the brain consists of the

forebrain, midbrain,hindbrain

the sequence of events that cause a muscle to contract can be summed up in the correct order as

detach, extend, attach, pull

the contacting surfaces of a moving joint, such as your hip joint, consist of


action potentials relay different intensities of information due to the

frequency of action potentials relative to the strength of the stimulus

which of the following statements about skeletal muscle fibers is true

each muscle fiber contains actin and myosin

the two major anatomical divisions of the nervous system are the

central nervous system and peripheral nervous system

Which of the following statements regarding sexual reproduction is true?

Sexual reproduction generates greater genetic variation than asexual reproduction.

In which part of the human female reproductive system does fertilization normally take place?


Human testes are positioned in an external sac rather than in the abdominal cavity

so the testes can be kept cooler than the body's interior.

Which of the following produces a thick fluid containing fructose, which is used for energy by sperm?

seminal vesicles

Which of the following statements comparing spermatogenesis and oogenesis is true?

Men, but not women, can produce gametes throughout their lives.

Which of the following STDs is caused by a virus that can also cause cancer?

genital warts

Sterilization, in which the sperm is surgically prevented from reaching the egg, is accomplished by

tubal ligation or vasectomy.

The function of a sperm cell's acrosome is to

carry enzymes that help the sperm penetrate the egg.

Which of the following serves as an impenetrable barrier that prevents more than one sperm from fertilizing an egg?

the vitelline layer

Which of the following occurs during the process of labor?

positive feedback involving oxytocin and prostaglandins

Mendel conducted his most memorable experiments on


An insect that has the genotype EeGGcc will have the same phenotype as an insect with the genotype _____.


In an individual of genotype Aa, where are the A and a alleles physically located?

One allele is on one chromosome, and the other is in the same position (locus) on the homologous chromosome.

The phenotypic ratio resulting from a dihybrid cross showing independent assortment is expected to be


Imagine that we mate two black Labrador dogs with normal vision and find that three of the puppies are like the parents, but one puppy is chocolate with normal vision and another is black with PRA (progressive retinal atrophy, a serious disease of vision). We can conclude that

the alleles for color and vision segregate independently during gamete formation.

Imagine that long fins in zebrafish is a dominant trait. A breeder wants to set up a breeding program beginning with homozygous dominant long-finned fish. If she obtains a handful of the long-finned fish, how can she tell which if any of these are homozygous for the trait?

Cross the long-finned fish with short-finned fish; if the offspring are all long-finned, the long-finned parent is homozygous.

Dr. Smith's parents have normal hearing. However, Dr. Smith has an inherited form of deafness. Deafness is a recessive trait that is associated with the abnormal allele d. The normal allele at this locus, associated with normal hearing, is D. Dr. Smith's parents could have which of the following genotypes?

Dd and Dd

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