The direct coombs’ test is designed to detect when people have a disease that causes them to
have an excessively high fever.
quit making antibodies.
make too many red blood cells.
produce antibodies that bind to their own red blood cells.

Ivan is looking at a cross section of a stem taken from a vascular plant. he sees two different types of vascular tissue: the xylem, which is closer to the center of the stem, and the phloem, located around the xylem, closer to the outside of the stem. how do these two structures work together in a living plant?

Substances that can pass through cell membranes by diffusion include a. na ions. b. proteins c. glucose. d. oxygen.

What organelle makes protein for use outside the cell?