Which makes viral infections difficult to defeat

(a) the immune system must attack the body’s own cells

(b) macrophages work slowly

(c) viruses live outside of cells

(d) viruses are attacked by a nonspecific immune response

Which of the following is not a defining characteristic of plants?

What is the next step in muscle contraction after the actin changes shape? (apex)

The current thought on the structure of the cell membrane is: a. a static phosphate sandwich of lipids b. a fluid-mosaic of phospholipids and proteins c. a bilayer of proteins with static lipid molecules d. an impermeable bilayer of protein molecules e. a static and permeable phospholipid single layer