Answer:
c) Vascular system
Explanation:
The vascular system of a plant are the phloem and xylem.
The xylem is responsible for movement of water from the roots to the leaves while the phloem us responsible for translocating nutrient and sugars ( carbohydrate) produced by the leaves to other areas of the plants that need them for growth.
Answer:
When blood glucose level rises beyond the threshold levels, the pancreas secrets hormones insulin. The latter ensures entry of glucose into the cells through Glut transporters for cellular utilization, therefore reducing the blood levels., and promotes storage as glycogen in the liver and muscles.
How ever if the glucose levels drops below the set point, an hormone glucagon is also produce by the pancreas to cause the liver o withdrawal and breakdown glucose storage as glycogen back to glucose thus raising the blood glucose level back to the normal levels.
This is an example of negative feedback mechanism, because the increase in the input levels (blood glucose levels) brings about a counter mechanisms (insulin secretions)as output , to reduce the elevated levels by promoting entry into the cells,, thus bringing the levels to threshold levels.
Thus insulin is acting in a negative feedback mechanism to control blood glucose levels
Explanation:
Toxicology is the study of poison on living things
Griffith learned that a chemical changed harmless cells into harmful cells.
