B- respiration or A- transport
The correct option is D.
Wind has some advantages which makes it suitable as a source of energy but it also possesses some disadvantages which reduces its potentials as a viable source of energy. For instance, large expanse of land will be needed to construct wind farms and this may not be feasible especially in populated areas. Another disadvantage is that electricity production will be depended on the availability of wind, when there is no wind, there will be no electricity.
Answer:
The correct option is <u><em>A. they evolved from land mammals.</em></u>
Explanation:
The process of evolution explains how closely one organism is to another based on their common ancestors. Scientists believe that those organisms which show many similarities in their structures or functions might have evolved from a common ancestor in the past.
As in the above-mentioned question, scientists have observed that cetaceans lack gills and breath air, this is a property of land mammals. The cetaceans have fin bones which are similar to the limb bones. As limb bones are present in land mammals, hence they cetaceans and land mammals might have common ancestors in the past.
