The lowest and thickest layer of the atmosphere is troposphere
Activation energy - is the minimum quantity of energy that the reacting species must possess in order to undergo a specified reaction.
Answer: Option D. Vestigial trait
Explanation:
Vestigial traits simply involves those traits (such as organs, structurrs or behaviors) which are found or occurs in organisms or animals, that have lost all or most of their original function through evolution. These vestigial structures were organs that performed some important functions in the organism at one point in the past. In most cases, organs or traits once identified as vestigial simply had an unrecognized function.