6. Which of the following statements are accurate?
A. In an average, healthy human, the partial pressure of carbon dioxide is usually higher in the blood in systemic veins than the alveoli
B. In an average, healthy human, the partial pressure of oxygen is usually higher in the systemic veins than the alveoli
C. In average, healthy human, the partial pressure of oxygen is usually higher in the systemic arteries than in the body tissues
D. Generally speaking, gases will diffuse down their pressure gradient
E. In an average, healthy human, the partial pressure of carbon dioxide is usually higher in the body tissues than the systemic arteries.

Read this summary of a scientific theory: "cells are the most basic structural and functional units of life. all living organisms are made up of one or more cells. all cells that are alive in the world today came from pre-existing cells." which of the following would require this theory to be modified? -a.) a survey finds that a majority of people believe viruses carry out the basic processes of life. -b.) a prominent scientist says she feels strongly that one day the theory will be challenged by life on other planets. -c.) the dna of unicellular and multi-cellular organisms is shown to have many fundamental similarities. -d.) scientific observations show that microscopic organisms living in the deep ocean are not made up of cells.

In a leaf, dermal tissue a) stores food b) stores carbon dioxide c) releases oxygen into the air d) transports water from the roots

Under which of the following circumstances would natural selection not operate on an organism