Phosphorous is:

A:found free in the atmosphere

B: returned to the soil by rhizobium

C: added to the soil though weathering

D: usually very abundant in an ecosystem

the median of the data is 4.5.

the answer to the blank provided is “an autosomal gene that is required for the expression of genes on the x chromosome”.

testis-determining factor, abbreviated as td, which is more popularly known as sex-determining region y or sry protein, is a dna-binding protein or  gene-regulatory protein/transcription factor, encoded by the  sry gene. it is the gene responsible for the initiation of male gender determination in humans.

plants absorb water from the soil by osmosis. root hair cells are adapted for this by having a large surface area to speed up osmosis. the absorbed water is transported through the roots to the rest of the plant where it is used for different purposes: it transports dissolved minerals around the plant.