Where is the frog's heart compared to its lungs?

Sarah performs an experiment to determine the effect of nitrogen on plants. she studies the effect of nitrogen on the growth of the root hair, height of the plants, and nodule formation. which factor is an independent variable?

Coral reefs are built by some cnidarias? true or false

Awoman with type a blood has a child with type a blood. which of the following men could not be the father of this child? their blood types are below. a. b b. any of these could be the father c. ab d. a