The answer is class and family.
<span>Taxonomic groups are used for biological classification. There are eight main taxonomic groups: domain, kingdom, phylum, class, order, family, genus and species, with the domain as the most inclusive and species as the least inclusive. If we take a look on Mammalia and Hominidae classification, we can assume that Mammalia represents class, and Hominidae represents family:</span>
<span>1. Domain: Eukarya</span>
<span>2. Kingdom: Animalia</span>
<span>3. Phylum: Chordata</span>
<span><u>4. Class: Mammalia</u></span>
<span>5. Order: Primates</span>
<span><u>6. Family: Hominidae</u></span>
<span>7. Genus: Homo</span>
<span>8. Species: Homo sapiens</span>
The body actually performs cellular respiration continuously. The correct option among all the answers that are given in the question is the third option or option "C". The other options that are given are wrong and so can be avoided. I hope the answer has actually come to your help.
Biologists do not fully understand DNA because there are constant changes and new discoveries developing.