The answer is because when the heart pumps blood in the artery during systole it counteracts the resistance provided by the blood vessels. This requires high pressure that is provided by the force of ejection due to the contraction of the ventricles. On the other hand, the pressure is lowest during diastole which is the ventricular filling of blood. There is low resistance in the blood vessels and the arterial wall pressure declines until the heart starts to contracts again.
The nervous and endocrine systems exert the ultimate control over homeostasis because they coordinate the functions of the body system
Answer:
The stem is normally divided into nodes and inter nodes.
2. Lateral buds and leaves grow out of stem at intervals called nodes.
Explanation:
Zooplankton ingest phytoplankton, along with any MeHg present in the phytoplankton but eliminate MeHg from their cells more slowly than they ingest it. This leads to bioaccumulation and magnification of MeHg concentrations in the zooplankton compared to the phytoplankton
Enzymes are biological catalysts which increase the rate of biochemical reactions without undergoing any change themselves. They bind with the substrate to form a enzyme substrate complex leding to the formation of product releasing free enzyme.
Enzymes have an optimum pH at which they show their maximum activity. Any change in the pH effects the enzyme and the enzymatic reaction. Most of the enzymes are functional at the neutral pH of 7 in the cell cytoplasm with a few exceptions. An acidic environment in the cell, changes the tertiary structure of the enzymes and the bonds of the enzymes are weakened. Thus, preventing the substrate binding to the active site of the enzyme and inhibiting catalysis. This is due to the change in the structure of the active site leading to the lack of electrostatic attraction between the enzyme and the substrate.