Ascientist took a boat trip across the atlantic. on his voyage, he found a lizard, but was unsure of the species. he used his dichotomous key because he wanted to know where the lizard came from, so he could return it to that general area.

D. for classifying organisms and studying biodiversity

Explanation:

A and C are irrelevant because there was only one organism to observe therefore the scientist could not observe how it interacted with others.  B is irrelevant because the scientist did not have an ecosystem to observe.

Explanation:

i take test

regulation of gene expression. gene expression can be regulated by various cellular processes with the aim to control the amount and nature of the expressed genes. these regulatory proteins bind to dna and send signals that indirectly control the rate of gene expression

explanation:

the answers are a and c