As a river’s slope increases, the power of the river to cause erosion usually decreases

thrombocytopenia, which is a deficiency in blood platelets, can cause bleeding and bruising in the dermis similar to senile purpura. other possible causes include: exposure to ultraviolet rays and aging skin are common causes of senile purpura. senile purpura may also be a sign of collagen loss in the skin and bones.

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.