Explanation:
Hence, the correct answer is 'Nuclear membrane'.

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.
The Americans colonies became free and independent states explanation: because they declared independence
<span>Intrinsic factor is a glycoprotein principally secreted by the parietal cells of the stomach. This secretion is needed to produce mature erythrocytes. Its secretion is governed by the same biochemical processes that regulate acid secretion and its action is to assist in the absorption of vitamin B12.</span>