<h2>a) is the correct option </h2>
Explanation:
The extracellular domain of the transmembrane receptor protein acts as binding site for primary messenger molecule whereas the transmembrane domain holds the receptor within membrane and the cytosolic domain has intrinsic tyrosine kinase activity, all these helps in proper cell signaling
If because of any mutation there is change in shape of the extracellular domain then that molecule that normally binds to the receptor protein will no longer attach hence cellular response will be deactivated
They would not be able to survive in an environment without sunlight. For instance, they would not be able to survive in caves, because they need sunlight for food and if there is no sunlight then they can not create food and would starve.
The organelle called the Mitochondria, also known as the powerhouse of the cell