Please state the options / choices so that we can answer your question. Thank you.
Nexin
This is the elastic protein among tubulin doublets that link them together for ciliary and flagellae structures.
Cilia and flagella are cellular structures that facilitate movement of the cell from one area to another.
This protein also inhibits movement on microtubules from axonemes.
The identify of the four DNA nucleotides is based on b) covalent bonds.
Scientists believe that great apes such as chimpanzees and gorillas are more closely related to humans based on the evolutionary timeline because apes are larger than monkeys and have long legs and no tails. Apes are known to have larger brains than monkeys which makes them so closely related to us. This fact cancels out B and C for the answer. Also, apes (gorillas, orangutans, etc.) are much larger than monkeys (mandrill, lesula, etc.). This right away cancels out option D. What's left is option A which features body parts and comparisons that are comparatively accurate towards humans. Hope this helped :))
The nucleolus is inside the nucleus