The major difference between prokaryotic and eukaryotic cells is that

B. All eukaryotes have membrane-bound organelles like the nucleus. Prokaryotes have no internal membrane-bound organelles.

d. planting trees

the trees take in carbon to make oxygen.

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.