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.
The nursing action that is best in achieving the goal is changing disposable diapers using a duration of 2 to 3 hours. This is by use of clean diapers. The changing of the diapers depend with how often he or she wets the diapers.when you change the diapers ensure that your hand is always clean.
A codon is a sequence of three nucleotides in DNA or RNA that codes for either a particular amino acid or tells the cellular machinery to start or stop using the code. It isn't located anywhere specific.