*Question*
Q: What occurs before the endometrium thickens in estrous cycles? Read this paragraph and choose the correct option from the provided answers: Choices: - fertilization - pregnancy - copulation - ovulation A:
**Answer**
ovulation

*Question*
Q: Hiv has proteins called what, internal to the envelope, which help stabilize virion shape? Read this paragraph and choose the correct option from the provided answers: Figure 21.4 Viruses can be either complex in shape or relatively simple. This figure shows three relatively complex virions: the bacteriophage T4, with its DNA-containing head group and tail fibers that attach to host cells; adenovirus, which uses spikes from its capsid to bind to host cells; and HIV, which uses glycoproteins embedded in its envelope to bind to host cells. Notice that HIV has proteins called matrix proteins, internal to the envelope, which help stabilize virion shape. (credit "bacteriophage, adenovirus": modification of work by NCBI, NIH; credit "HIV retrovirus": modification of work by NIAID, NIH). Choices: - reduction proteins - step proteins - sphere proteins - matrix proteins A:
**Answer**
matrix proteins

*Question*
Q: What do ranchers fear will happen if wolves return? Read this paragraph and choose the correct option from the provided answers: Choices: - loss of environment - human predation - vegetation predation - livestock predation A:
**Answer**
livestock predation

*Question*
Q: What kind of weather change do la nina years usually bring? Read this paragraph and choose the correct option from the provided answers: El Nino and La Nina bring about dramatic changes in climate for a year or two. In some locations, one brings rain and the other brings drought. In California, for example, El Nino years are full of snow and rain. La Nina years tend toward drought. These variations can bring tremendous changes to living creatures. Humans are also affected; for example, erosion from storms may be very high some years. Choices: - heat - Mass amounts of snow - moisture - drought A:
**Answer**
drought