Directional selection acts against:

both extremes simultaneously in the variation of the trait

one of the extremes in variation

the average or mean value for the population

none of these

How does multicellular organisms grow?

What would occur if the repressor of an inducible operon were mutated so it could not bind the operator? a. irreversible binding of the repressor to the promoter b. reduced transcription of the operon's genes c.

In a population, the changes in allelic frequencies of a gene that are due to chance.

Which limiting factor will most likely affect a tree population regardless of its density? A) competition with a nonnative tree species B) the introduction of an insect-born disease C) competition with individuals of its own D) a widespread drought

An organism has 100 offspring, but 80 percent of them die within the first three months. This organism is most likely a (an) pelican, lizard, dandelion or orangutan?

Is the cell wall or cell membrane composed of two layers of lipids and proteins?

What kind of cells is an amoeba?

What happens when you get scared "Half to death twice"?

Atoms of different elements combine to form

How does mRNA differ from DNA? a. mRNA contains ribose sugars; DNA contains deoxyribose sugars. b. mRNA contains the base uracil; DNA contains the base thymine. c. mRNA is single-stranded; DNA is double-stranded. d. All of the above are correct.