Chargaff's rule states that the amounts of guanine and cytosine are roughly the same, and the amounts of adenine and thymine are roughly the same

a. in eukaryotes only. the rule doesn't apply to prokaryotes.
b. but the relative amounts of g+c and a+t vary by species.
c. except in species that use uracil in place of thymine in their dna.
d. and the relative amounts of g+c and a+t don't vary by species.

B

Explanation:

This is because of the base pairing rule in DNA. Guanine (G) pairs with Cytosine(C) while Adenine(A) pairs with Thiamine (T). Therefore, the amount of G will relatively be generally equal l to that of C while that of A will be generally equal to that of T. The amount of the complimentary base pairs will, therefore, be equal.

the correct answer is option b

behavioral response need communication and thus co-ordination at several levels such as interaction among cells, organ system and the entire organism.

behavioral response produces both internal and environmental stimulus.

all these collisions do one thing, and that thing is explained in the last option. when dusst, rocks and ice collide, they harden and form giant layers of rocks or hard ice.

d)   to harden materials to form different parts of earth’s layers

hope it ,

bioteacher101