Xylem transport water and minerals upward
transport food downward
is only found in the roots of a plant
is a plant's outer layer of cells

Answer is transport water and minerals upward

Explanation:

the vascular tissue in plants that conducts water and dissolved nutrients upward from the root and also helps to form the woody element in the stem.

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.

a. to encourage apoptosis