NAD is the electron carrier which is used in redox reactions in cellular respiration
D oxygen there was no free oxygen on the earth
Most bacteria are heterotrophic decomposers, which means they depend on other organisms for food and feed on dead matter.
A seedling is a young plant sporophyte creating out of a plant incipient organism from a seed. Seedling improvement begins with germination of the seed. A common youthful seedling comprises of three fundamental parts: the radicle, the hypocotyl, and the cotyledons.
It gives you a sign that digestion is having a hard time taking place.
