cells contain homologous pairs of chromosomes. A. Haploid
B. diploid
C. tetraploid
D. gametes
E. sex cells

B, Diploid

Explanation is here:

Somatic cells are sometimes referred to as “body” cells. Homologous chromosomes are matched pairs containing the same genes in identical locations along their length. Diploid organisms inherit one copy of each homologous chromosome from each parent; all together, they are considered a full set of chromosomes.

segmentation=endoskeleton=backbone=coelom=tissues

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.