Biology is the study of natural science (nature) and it is important to humans cause we learn about it
D.
They have the same number of protons as electrons.
Explanation:
Protons are found in the nucleus of the atom and have a positive charge while electrons orbit around the nucleus and have a negative charge. Usually, in a neutral atom of an element, the number of protons is equal to the number of electrons. This is why the atom has no charge because the positive and negative charges cancel out. When an atom loses an electron its charge turns positive while when it gains an electron its charge turns negative.
Answer: A missense mutation changes the identity of a codon from one amino acid to another, resulting in a change to the protein primary structure. A silent mutation occurs when a mutation does not change the amino acid coded for by that codon.
Explanation:
The alveoli are surrounded by tiny blood vessels, called capillaries carrying blood to and from the heart.