Why do individuals with low levels of fitness die?

How do adaptations help an organism as they struggle for existence?

low level of fitness means the individuals have little or no adaptations.

while adaptations are those changes that help an organism to struggle and survive. it increases the survival rate of an organism. adaptations are the changes in DNA in the form of mutations and recombinations. it increase immunity of an organism and improve its fitness.

Explanation:

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.