Why do roots always grow in a downward direction, no matter which way you turn the seed or seedling? because roots weigh more than any other plant part
because the plant’s stem begins to grow, and it pushes the roots downward
because that is the direction that roots find necessary water and nutrients
because the root contains hormones that make it grow away from the sun

C. because that is the direction that roots find necessary water and nutrients

Explanation:

Water and nutrients are in the soil, so roots need to grow down to absorb them.

A is incorrect because the effect of gravity is not strong enough to pull something into the ground.

B is incorrect because the stem grows up and does not push down on the roots.

D is incorrect because those hormones don't exist.

explanation:

b,bacteria convert nitrates

into nitrogen gas.

d,plants and animals take in

and use nitrogen compounds.

e,bacteria break down waste    

products and return nitrogen  

to the soil.

a,bacteria convert atmospheric

nitrogen to ammonia.

c,bacteria convert ammonia

to nitrites and nitrates.