I only have one reason but hope it helps!
Because without those bases pairing there <span>would be no structure of a DNA.</span>
The answer A. DNA in the nucleus controls all cell activity.
They are a very good example of mutualism in which each species benefits. Please mark Brainliest!!!
The seven steps of the scientific method start with observing the occurrence or asking a question, researching the topic, forming a hypothesis, designing and conducting an experiment, analyzing results, drawing a conclusion and reporting results.
D- a bond in which electrons are transferred