I think its the atmosphere ?????
you are correct, it would be D. i hope this helps you out!
Reactants. Reactants are the substances that are needed for a chemical reaction to occur. Without reactants there are no products.
The correct answer is - They supply the energy needed for living processes.
Both the carbon and the nitrogen, are gases that are crucial for the survival of the organisms on the planet. They are mostly used by the producers in the ecosystems, as they need them to manage to perform their cycles, get nutrition, and of course energy. The producers are the basis of the ecosystems, so if they do not have a healthy supply of carbon and nitrogen, the ecosystems on the whole planet will collapse. The carbon and the nitrogen later go from one organism to another as the energy is transferred, and usually end up back into the atmosphere again.
Answer: Read explanation
Explanation: there’s actually no similarity at all. A cell membrane is made of phospholipids, globular proteins, glycolipids, glycoproteins, and cholesterol, and has passages that serve explicitly for passive and active transport of materials through it.
The skin is made of cells and dead keratin and serves as much as possible to prevent most substances from moving through it. It’s “designed” for toughness and distensibility, not for selective permeability.
All in all, the difference is that a cell membrane is explicitly and only for the passing and transport of materials through it, and the skin in the skin is made to be tough and durable, almost the opposite of a cell membrane.