When put together, these bases (A, T,C, G) make up "sentences" that we call

Explanation:

ATCG are called the Nitrogenous Base. The DNA(deoxyribonucleic acid) is made up of a phosphate group, 5 Carbon sugar called deoxyribose and Nitrogenous base.

This Nitrogenous bases are further divided into purine and pyrimidine

Purine includes- Adenine and Guanine while pyrimidine includes Thymine and Cytosine or Uracil in the RNA.

When Base pair occurs, Adenine pairs with Thymine while Guanine pairs up with cytosine in DNA.

a symbiotic relationship with the mitochondria

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.