Once a neuron has reached threshold voltage, the depolarization is a result of the opening of a .

Which of these substances does not protect against invaders in the nonspecific immune response? a. saliva b. mucus c. tears d. urine

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

What do isotopes of uranium have the same number of? what do they have a different number of? a) same number of protons; different number of electrons b) same number of protons; different number of neutrons c) same number of electrons; different number of protons d) same number of neutrons; different number of protons