Which is an example of positive gravitropism?
a. the plant shoot growing up out of the soil
b. the plant flower opening with the sunrise
c. the plant root growing down into the soil
d. the plant turning towards the sun

c. the plant root growing down into the soil

Explanation:

The plant root going down deep into the soil is an example of positive gravitropism. Gravity pulls everything towards the center of earth i.e. downwards and roots follow the direction of gravity automatically by growing downward towards soil that is why it is known as positive gravitropism. In short we can say that root favors the direction of gravity.

Shoot on the other hand show negative geotropism/gravitropism i.e. it grows towards the opposite direction of gravity. Shoot grow towards upside direction i.e. away from the surface towards sky.

answer; ///i believe that the correct answer is (e); check first good

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.