<span>I believe the answer is: D. proteins
The main functions of these proteins is to allow specific substance to pass through the membrane of the cells which needed for the energy formation for cells'functions.It created through the combination of more than 20 amino acids with different functions.</span><span />
Answer:
materials move against a concentration gradient
Answer:
if these mixtures are feed as only source of food African grey parrots become ill and ultimately die.
not sure about the answer but see if this is correct.
True, muscle tension can make the muscle sore or it can even pull it. Muscle fatigue is the first step for pulling a muscle.
