Which of the following is a biotic factor of an ecosystem? *

a. grass

b. a rock

c. air

A disease can be a problem one year but not the next in the same crop because A. there is no way to predict where disease will occur. B. variables, like weather, impact the presence of disease. C.

The ascending limb of the loop of henle is permeable to water. the ascending limb of the loop of henle is permeable to water. a. True b. False

Which parts are in the nucleus

A group of scientists wants to test the effects of increased salinity on a population of catfish in a river. what result from this experiment would confirm that natural selection is a process that can drive evolution?

What it called when daughter cells get an exact copy of dna from the parent cell

A scientist begins working by trying to explain a natural occurence that is

Which label belongs in the area marked x?

Which of the following may happen to astronauts when they return to Earth from space? They may feel dizzy because the flow of blood to and from the heart to the brain is affected in space.

Under what conditions might the morphological species concept be used instead of the biological species concept? a. It is clear that one species evolved into another, based on fossils. b.

If the earth traps more heat, it may cause