Which monomers vary based on the structure of their side chains

correct answer is option a.

tropopause, stratopause and mesopause have all in common aspect that is point of maximum temperature in its layer of the atmosphere. all layers of atmosphere observe abrupt change in temperature. tropopause is the boundary between troposphere and stratosphere. stratopause is the boundary between stratosphere and mesosphere. mesopause is the boundary between mesosphere and thermosphere. these all boundaries are ranges between altitude of 0 to 80 km.

preservation because he preserves part of the land and preserves means save

explanation:

as many times as you want

because the light is a great source of energy for the plants to survive. (i hope this )