thymine
adenine
cytosine
guanine
Explanation:
uracil is not because uracil is only RNA.
According to the cephalocaudal trend, the head develops more rapidly during the prenatal period than the lower part of the body.
<h3>What is Cephalocaudal trend?</h3>
This refers to the pattern of growth during the prenatal stage in which the head grows more than the other parts of the body.
This is therefore the reason why option B was chosen as the most appropriate choice.
Read more about Cephalocaudal trend here brainly.com/question/9562393
<span> RNA was thought of as little more than a messenger between DNA and proteins, carrying instructions as messenger RNA (mRNA) to build proteins. However, RNA can do far more. It can drive chemical reactions, like proteins, and carries genetic information, like DNA. And because RNA can do both these jobs, most scientists think life as we know it began in an RNA world, without DNA and proteins.</span>