Propose an experiment to test whether $Pilobolus$ shoots its sporangia preferentially toward light. Hypothesize why such a preference might be advantageous.

$Pilobolus$ is a zygomycete, and the sporangia just described produce asexual spores. In contrast, which of the following best describes what happens during the sexual phase of its life cycle?

a. It produces eight ascospores in each ascus.
b. It produces basidiospores that grow into mushrooms.
c. It produces motile sperm and eggs.
d. Hyphae from two compatible mating types fuse and form a zygosporangium.

What does it mean to say that a hypha is dikaryotic?

a. Two nuclei fuse during sexual reproduction to form a zygote.
b. Two independent nuclei, derived from different individuals, are present in each cell.
c. The nucleus is diploid or polyploid-not haploid.
d. It is extremely highly branched, which increases its surface area and thus absorptive capacity.

The hyphae of arbuscular mycorrhizal fungi (AMF) form bushy structures after making contact with the plasma membrane of a root cell. What is the function of these structures?

a. They anchor the fungus inside the root, so the association is more permanent.
b. They increase the surface area available for the transfer of nutrients.
c. They produce toxins that protect the plant cells against herbivores.
d. They break down cellulose and lignin in the plant cell wall.

Angiosperms such as grasses, oaks, and maples are wind pollinated. The ancestors of these subgroups were probably pollinated by insects, however. As an adaptive advantage, why might a species "revert" to wind pollination? Why is it logical to observe that wind-pollinated species usually grow in dense stands containing many individuals of the same species? Why is it logical to observe that in wind-pollinated deciduous trees, flowers form very early in spring - before leaves form?

What trait(s) define(s) the vertebrates?

A) Jaws and a spinal cord.

B) Endoskeleton constructed of bone.

C) Notochord and a post-anal-tail.

D) Vertebrae and cranium.

Suppose that a gene originally identified in nematodes (roundworms) is found to be homologous with a gene that can cause developmental abnormalities in humans. Would it be possible to use fruit flies as a model organism to study this gene? Explain.

Which of these characteristics does not apply to cnidarians?

a. are diploblastic
b. possess a gastrovascular cavity with one opening
c. undergo metamorphosis
d. have a central nervous system

What determines the primary structure of a DNA molecule?

a. stem-and-loop configuration
b. complementary base pairing
c. deoxyribonucleotide sequence
d. hydrophobic interactions and hydrogen bonding

Explain the process of extracellular digestion that occurs during the growth of $Pilobolus$ mycelia through dung.

The gravitational force of a star on orbiting planet 1 is F_1. Planet 2, which is twice as massive as planet 1 and orbits at twice the distance from the star, experiences gravitational force F_2. What is the ratio F_1/F_2?

A meter stick is balanced on a support at its center. A 0.70-N weight is hung on the meter stick a distance $0.25 \mathrm{~m}$ to the left of the center. Where should you place a $0.40-\mathrm{N}$ weight so that the meter stick is in static equilibrium? Determine the force exerted by the support on the meter stick.

A meter stick balances horizontally on a knife-edge at the 50.0 cm mark. With two 5.0 g coins stacked over the 12.0 cm mark, the stick is found to balance at the 45.5 cm mark. What is the mass of the meter stick?

The dwarf planet Praamzius is estimated to have a diameter of about $300 \mathrm{~km}$ and orbits the sun at a distance of $6.4 \times 10^{12} \mathrm{~m}$. What is its orbital period in years?