Answer:
Part 1:
The four astronomical bodies one could choose to represent the 4 labels in the diagram are
A - universe
B - galaxy
C - solar system
D - Mars
The universe contains galaxies and galaxies holds solar systems which have planets like Mars
Part 2: D or a planet like Mars is unlike all their other astronomical bodies it does not have other astronomical bodies within it thus, its different from rest.
I’m not entirely sure about what you’re asking but chargaff’s rule is the thing that states that the amount of each “letter” in DNA is equal to its pair. Guanine (g) pairs with cytosine (C) and the same with adenine(A) and thymine (T). I’m sorry my answer is so vague, but I hope it helps a little!
<span>B. tiny structures in the cell that carry out the cell's activities</span>