How is a dichotomous key used?
a. the organism is compared to paired pictures of organisms until a match is found in the key.
b. the organism’s dna is sequenced and compared to the dna sequences that are listed in the dichotomous key.
c. observable characteristics of the organism are checked through a sequence of two-part steps until an identification is listed in the key.
d. observable characteristics of the organism are listed in a group and compared to different groups of observable characteristics listed in the key.

c.Observable characteristics of the organism are checked through a sequence of two-part steps until an identification is listed in the key.

Explanation:

Dichotomous key is the term used to describe a method of identifying living beings, such as identifying a species of butterfly that we are observing, for example. This method is composed of a step key that gives two answer options, which someone follows until reaching the result. In other words, a dichotomous key allows the observable characteristics of an organism to be verified through a sequence of steps in two parts until an identification is listed in the key.

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explanation:

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hey, i believe your answer would be d. sugar ribose and the base uracil. i believe this is the answer, because rna consists of sugar ribose, adenine, guanine, cytosine, and uracil.

your first option is incorrect, because that's dna. where it consists of sugar deoxyribose, adenine, guanine, cytosine and thymine.

your second option is also incorrect, this is because sugar deoxyribose is in dna, and uracil is in rna. these two do not make sense together.

your third option being incorrect, because sugar ribose is in rna, but not the base of thymine. rna consists of uracil, not thymine.

lastly your fourth option being correct! this answer is correct, because both sugar ribose, and the base uracil are in rna! ~

answer is d. sugar ribose and the base uracil.