The is the coldest layer of the atmosphere.
a.
troposphere
b.
stratosphere
c.
mesosphere
d.
thermosphere

The mesosphere is a layer between thermosphere and stratosphere it is the highest layer of the atmosphere in which all the gases are mixed up rather than being layered by their mass. It is the coldest part of our atmosphere, the temperature can reach upto -90 degree Celsius. The air is much thinner in mesosphere. Due to less air particles, not enough heat is absorbed which is eventually lead to a colder temperature making it mesosphere the coldest layer of the atmosphere.

The gens present in the dna in the nucleus of the cell in the body