ON A TEST
Which one of the following is true of a vaccine?
(a) A vaccine kills the harmful bacteria in the body. (b) Vaccines destroy new pathogens as they enter the body. (c) Vaccines stimulate the body’s immune system to produce antibodies.
(d) Vaccines produce toxins that destroy pathogens.

In what for do plants utilize nitrogen? why do they need nitrogen?

Most animal cell membranes have proteins that pump. ions out of the cell and potassium ions into this

Which statement is the best summary of the model? a-a series of aerobic and anaerobic reactions take place in cells b- the sun's energy moves through trophic levels in a food chain c-light energy is converted into stored chemical energy plants.d- food molecules are broken down in the cells if living things.