The answer is B) These fuels are available in a limited supply- - when the fuel is used it is no longer available.
Answer:
answer is 2 for both cuz they both have the 2 subscript next to hydrogen
well both are considered macromolecules. proteins are like big lego construction. each single piece gets pieced together to make a larger thing. each single piece is a monomer, and the larger construction is the polymer. the monomers are called amino acids and they get pieced together to form the polymer which is called a protein. the linkage that they use is an amide bond, and in biology it is usually called a peptide bond. carbohydrates can be singular monomers or polymer units. they are made of completely different compounds usually aldehydes or ketones. and they link together through different chemical linkages (acetal or ketal linkages for polymers, hemiacetal or hemiketal linkages for monomers). both can be large, 3D strucutres proteins are only functional as a large, 3D structure, while carbohydrates can be singular. (you might wanna word it differently for safety reason)
I think the correct answer from the choices listed above is option A. Glacial episodes are an example of a positive feedback. Each glacial period in the Earth is subjected to a positive feedback which makes each period more severe. Hope this answers the question.
