<h2>B) option is correct </h2>
Explanation:
Natural selection is a selection pressure which operates in a population and allow the best fitted genotype to survive in changing environmental conditions and eliminate the other genotype which are not fit
In artificial selection, breeders select superior breed for the breeding purpose so that this type of selection favors the superior genotype and eliminates inferior genotype, thus leading to genetic drift
Stabilizing selection is a type of natural selection in which intermediate genotype is favored but extreme genotypes (inferior and superior) are eliminated
In the given example of pigmentation in pigeons, breeding is selectively done with intermediate pigmentation hence intermediate genotypes will be favored
A ecosystem productivity is a rate of generation of biomass.’’I know this because it states.”In economy productivity refers to the rate of generation of biomass in an economy.This shows that the economy its usually expressed in units of mass per unit.
Answer:

Explanation:
To differentiate: 
Solution:
Use product rule:
and the following formulae:

![(10\,sinx\,\,cos x)'=10[(sinx)'cosx+(sinx)(cosx)']\\\\=10[cosx\,cosx-sinx\,sinx]\\\\=10[cos^2x-sin^2x]](https://tex.z-dn.net/?f=%2810%5C%2Csinx%5C%2C%5C%2Ccos%20x%29%27%3D10%5B%28sinx%29%27cosx%2B%28sinx%29%28cosx%29%27%5D%5C%5C%5C%5C%3D10%5Bcosx%5C%2Ccosx-sinx%5C%2Csinx%5D%5C%5C%5C%5C%3D10%5Bcos%5E2x-sin%5E2x%5D)
Use 

Static Electricity - the word static means 'at rest' - this kind of electricity exists when objects separated by an insulator has a build up of opposite charges. Because the attraction between these charges is so strong, they can flow even through great insulators. Ex: lightning, friction
Current Electricity - it makes electronic devices possible. There is a constant flow of charges in this type of electricity. In contrast to static electricity, current electricity is changing, dynamic and always on the move. Ex: starting a car, watching TV, using an electric stove.