A is the answer. It’s like addition.
Plants do carry out cellular respiration
They use it to convert glucose, a product from photosynthesis, into ATP, the energy carrying molecule
Btw plants and animals carry out cellular respiration
ONLY PLANTS carry out photosynthesis because they make their own food but they still need to convert it into energy
when cells spilt into 2 or more new cells
But this rule rule is applicable only for double stranded DNA molecule. The possibility of Adenine=40% and Thymine=60% is only in single stranded DNA molecule. In the question, the DNA sample referred is a single stranded DNA. hope it helps :D