What is significant about the amino acid methionine in protein synthesis

It is classed as an essential amino acid and cannot be synthesized by the body itself. ... Besides cysteine, methionine is the only sulphur-containing amino acid. Furthermore methionine plays an important role in the synthesis of other proteins, such as carnitine or melatonine

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.