Structures in plant leaves that open and close to maintain homeostasis are called stomata. This is where gases would diffuse in and out of the leaf.
The answer is, D. Organ system
Exercise is very vital to the body,it a form of physical activity.the sole aim of excercise is to maintain stamina, flexibility,keep fit and be overly healthy and well.
When we excercise, our heart rate increases and then it returns to the normal rate when with rest,when we take a break.there is reflection of vasoconstriction in the fingers as the blood is shunted to only the exercising muscles because it is noted that the pulse amplitude of the heart is always small after excercise and and increases slowly during recovery.
The amount of blood the heart pumps in a minute,that is the amount of blood ejected by the contraction of the left ventricle into systemic circulation increases when we are exercising and resistance to blood flow by skeletal muscles decreases.the blood vessels will try to adapt to the condition (exercise) inorder to control blood flow and as well meet energy demands.
When we finish exercising,our body temperature increases which will inturn cause increase in the pulse rate and the blood in our body makes way to our skin,hands and legs inorder to clear off the energy that was generated by the body(muscles) during exercise
Every protein has in itself molecular parts that function like zip codes and are used to designate where the protein must travel.