Choose the best answer to following. Explain your reasoning with one or more complete sentences.
Which of the following does inflation help to explain?
(a) the uniformity of the cosmic microwave background
(b) the amount of helium in the universe
(c) the temperature of the cosmic microwave background

APA style is typically used by writers and students creating writing projects in which of the following areas?

A. Social sciences

B. Language arts

C. Humanities

D. Literary critique

Which of the following subject areas is an example of a natural science?

a) philosophy

b) anthropology

c) psychology

d) astronomy

Choose the best answer for the following question.
When the universe was 380,000 years old, its thermal radiation spectrum consisted mostly of
(a) radio and microwave photons.
(b) visible and infrared photons.
(c) X-ray and ultraviolet photons.

Life on Earth began in water. What were some of the major adaptations that animals evolved that allowed them to survive out of water?

Complete the concept map.

Complete the concept map.

Answer the following questions based on the information provided.
How much cooler is the universe now (at an age of $4\times10^{17}$ s) than it was at an age of 1 second?
a. Its current temperature is one hundred-millionth ($10^{-8}$) the temperature at an age of 1 second.
b. Its current temperature is one hundred-thousandth ($10^{-5}$) the temperature at an age of 1 second.
c. Its current temperature is one-hundredth ($10^{-2}$) the temperature at an age of 1 second.
d. Its current temperature is one ten-billionth ($10^{-10}$) the temperature at an age of 1 second.

What are the four forces that operate in the universe today? Why do we think there were fewer forces operating in the early universe?

Choose the best answer for the following question.
Which of the following does not provide strong evidence for the Big Bang theory?
(a) observations of the cosmic microwave background
(b) observations of the amount of hydrogen in the universe
(c) observations of the ratio of helium to hydrogen in the universe

Choose the best answer for the following question.
When a proton and an antiproton collide, they
(a) repel each other.
(b) fuse together.
(c) convert into two photons.

Describe what a segmented body plan looks like. Which phylum includes animals with segmented bodies?

The animal phylum most like the protists that gave rise to the animal kingdom is _____.

Match the organism with its skeleton. A skeleton type may be used more than once.

$$\begin{matrix} \text{Organism} & \text{Skeleton Type}\\ \text{dog} & \text{A. hydrostatic skeleton}\\ \text{ } & \text{B. exoskeleton}\\ \text{ } & \text{C. endoskeleton}\\ \end{matrix}$$