Step-by-step explanation:
(9) Acceleration due to gravity is defined as the acceleration between two massive bodies when they are moving under free fall.
The relation between g and G is given by :
Where
G is universal gravitational constant
M is mass of the earth
r is distance
(10) The unwanted product that can toxify the crops are called weeds. To control weeds, a chemical called weedicides are sprayed in the field. Some other methods to control them are Ploughing or tilling of soil etc.