Always 23 because 23+23 is 46 All humans have 46 chromosomes 23 from dad 23 from mom
Explanation:
In contrast, commensalism can be defined as an intraspecific relationship in which one species (the commensal) obtains benefits such as food, shelter, or locomotion from another species (the host) without causing adverse effects. ... The host is unaffected, whereas the commensal can receive great benefits.
Two of the four major divisions in the geologic time scale are the Archean eon and proterozoic eon.
<u>Explanation:</u>
The Arcean eon is dated from 3900 million years ago to 2500 million years ago. It was in this period the oldest known rocks were deposited. At that time the atmosphere of earth was composed of gases like methane, carbon monoxide, ammonia etc.
The Proterozoic eon is dated from 2500 million years ago to 540 million years ago. It was by the end of Proterozoic era that the Eukaryotas came into existence.
There are some similarities and differences between Archean eon and Proterozoic eon. Stromatolites formed by the colonies of cyanobacteria lived in both the eras. This is one similarity between both the eras.
The weather in the Archean era was hot and wet while the climate and weather of proterozoic era was different from this. Proterozoic era experienced two ice ages.
These are the nitrogenous bases in a nucleotide. There are four, which you mentioned in the problem: adenine, thymine, guanine, and cytosine.
The other two parts of a nucleotide make up he backbone: sugar, deoxyribose (DNA=DEOXYRIBOnucleic acid) and the phosphate group.
Hope this helps!!
