How do scientists think protobionts formed?

A common garden pea has nucleotides that are 15% adenine. what percentage of thymine, cytosine and guanine would be present?

Which of these is an Active Transport

Which of these is characteristic of the photic zone of a freshwater ecosystem?

How does a virus infect a host cell? A. It lays its lipids on a host cell. B. It lays its proteins on a host cell. C. It injects its nucleic acids into a host cell. D. It injects its carbohydrates into a host cell.

Hemoglobin protein is produced by red blood cells, but liver cells from the same organism do not produce hemoglobin protein. Why? A. The gene for hemoglobin is missing in liver cells B. the gene for hemoglobin is turned off in liver cells C.

Why might it be particularly beneficial for the giant spider crab to be so large?

In which stage of growth do plants rest or grow very little?

Scientists have debated the evolution of three life forms: reptiles, birds and dinosaurs. After many years of reviewing fossil records scientists proposed the evolutionary relationship seen above in the cladogram.

The PNS is divided into several subsystems. What two subsystems form the first major division of the PNS? sensory and motor somatic and autonomic parasympathetic and sympathetic CNS and brain

Consider the model of the food chain. Imagine there is a herbicide poison spill and all the grass is killed. How will this influence the food chain model? A) The grasshoppers will die out. B) All of the consumers will decrease.