In grafting, the plant with the root system is called the , and the portion of the plant with the buds is called the .

In grafting, the plant with the root system is called the root stock , and the portion of the plant with the buds is called the scion

Explanation:

Grafting is a process of “vegetative mode of propagation “ in which  two parts of same or two different species of plants are joined together to make them grow as a single plant. The part of the plant which is kept over and above the other plant is called the “scion” while the part of the other plant kept at the bottom is called a rootstock.  

Thus, in grafting, the plant with the root system is kept at the bottom and hence it is called as root stock , and the portion of the plant with the buds is kept over and above the root stock and hence it is called as scion.

chlorophyll a: this is the most abundant pigment in plants. chlorophyll a absorbs light with wavelengths of 430nm(blue) and 662nm(red). it reflects green light strongly so it appears green to us.

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."