- Seeds have many different forms. Some are lightweight and are easily blown by the wind. Others are coated with burrs
and stick to animals' fur or are spherical and roll easily.
How is the survival of plants related to the form of seeds?
Seeds must germinate away from the
parent plant in order to have access to
enough light and moisture.
Seeds with unusual forms are not
attractive to animals, so they are not
eaten.
Seeds are camouflaged within the
parent plant so that they are not eaten
by insects.
Seeds are designed to germinate when
the correct soil type is located

What do all macromolecules have in common with each other? oa. they all are formed from the same elements. ob. they all have major roles in cell membranesoc. they all act as catalysts in the body. od. they all have peptide bonds between carbon atoms.

If bacteria are much too small to see, what is one reason why can we see colonies in the petri dishes that have plenty of food to eat after only a few days?

To answer this question, researchers studied populations of the dusky salamander (desmognathus ochrophaeus) living on different mountain ranges in the southern appalachian mountains. the researchers tested the reproductive isolation of pairs of salamander populations by leaving one male and one female together and later checking the females for the presence of sperm. four mating combinations were tested for each pair of populations (a and b)—two within the same population (female a with male a and female b with male b) and two between populations (female a with male b and female b with male a). the proportion of successful matings for each mating combination was measured. for example, when all the matings of a particular combination were successful, the researchers gave it a value of 1; when none of the matings were successful, they gave it a value of 0. then the researchers calculated an index of reproductive isolation that ranged from 0 (no isolation) to 2 (full isolation). the reproductive isolation value for two populations is the sum of the proportion of successful matings of each type within populations (aa + bb) minus the sum of the proportion of successful matings of each type between populations (ab + ba). the table provides data for the geographic distances and reproductive isolation values for 27 pairs of dusky salamander populations.