Natural selection relates the adaptations organisms have to their fitness for survival within their environment. According to the theory of evolution by natural selection, what must take place in an environment in order for one characteristic of a species to be selected over another?

chromosomes carry the genetic information for organisms. also, chromatin is the thread like dna which is located in the nucleus of an organism.

the answer for this question would be d. glaciers

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds