<span> A. a process by which organism keep internal conditions relatively constant despite changes in external conditions. </span>
Polar amino acids tend to be hydrophilic, meaning that they bond to water. These are those that establish hydrogen bonds to water. They are considered polar because they have a R group that's hydrophilic. Because of this characteristic, in a protein they tend to a be a at the surface maintaining contact with the surrounding solutions. The most common polar amino acids are: arginine, lysine, glutamic acid, and aspartic acid.
If the reproductive isolation between two species is complete, they cannot produce viable offspring. There is not enough information to determine if they did or didn't have a recent common ancestor
D.uracil is the nitrogen base bind with adenine
