(Q).
Answer the following question given this paragraph:   Energy Budgets, Reproductive Costs, and Sexual Selection in Drosophila Research into how animals allocate their energy resources for growth, maintenance, and reproduction has used a variety of experimental animal models. Some of this work has been done using the common fruit fly, Drosophila melanogaster. Studies have shown that not only does reproduction have a cost as far as how long male fruit flies live, but also fruit flies that have already mated several times have limited sperm remaining for reproduction. Fruit flies maximize their last chances at reproduction by selecting optimal mates. In a 1981 study, male fruit flies were placed in enclosures with either virgin or inseminated females. The males that mated with virgin females had shorter life spans than those in contact with the same number of inseminated females with which they were unable to mate. This effect occurred regardless of how large (indicative of their age) the males were. Thus, males that did not mate lived longer, allowing them more opportunities to find mates in the future. More recent studies, performed in 2006, show how males select the female with which they will mate and [3] how this is affected by previous matings (Figure 45.8). Males were allowed to select between smaller and larger females. Findings showed that larger females had greater fecundity, producing twice as many offspring per mating as the smaller females did. Males that had previously mated, and thus had lower supplies of sperm, were termed “resource-depleted,” while males that had not mated were termed “nonresource-depleted. ” The study showed that although non-resource-depleted males preferentially mated with larger females, this selection of partners was more pronounced in the resource-depleted males. Thus, males with depleted sperm supplies, which were limited in the number of times that they could mate before they replenished their sperm supply, selected larger, more fecund females, thus maximizing their chances for offspring. This study was one of the first to...   Q: Studies have shown that not only does reproduction have a cost as far as how long male fruit flies live, but also fruit flies that have already mated several times have limited amounts of this?   Choices:  - dna  - eggs  - chromosomes  - sperm  A:
(A).
sperm


(Q).
Answer the following question given this paragraph:   The primary feature shared by all vertebrates is the vertebral column , or backbone. The vertebral column protects the spinal cord.   Q: What does the vertebral column , or backbone, protect?   Choices:  - disks  - neurons  - axons  - spinal cord  A:
(A).
spinal cord


(Q).
Answer the following question given this paragraph:   Water is the most common substance on Earth, and most of it exists in the liquid state. A liquid is one of four well-known states of matter, along with solid, gas, and plasma states. The particles of liquids are in close contact with each other but not as tightly packed as the particles in solids. The particles can slip past one another and take the shape of their container. However, they cannot pull apart and spread out to take the volume of their container, as particles of a gas can. If the volume of a liquid is less than the volume of its container, the top surface of the liquid will be exposed to the air, like the vinegar in the bottle pictured in the Figure below .   Q: The most common substance on earth, water, is primarily present in what state?   Choices:  - gas  - solid  - freshwater  - liquid  A:
(A).

liquid