18.substrate-level phosphorylation
(a) energy released from atp hydrolysis is used to phosphorylate the substrate
(b) energy released from the chemical reaction is used to directly phosphorylate adp
(c) energy released from atp hydrolysis is used to phosphorylate adp
(d) energy released from the chemical reaction is used to directly reduce nad+

The correct answer is B energy released from chemical reaction is used to directly phosphorylate ADP.

Explanation:

When ATP molecule is formed by the phosphorylation of ADP but without the involvement of oxidative phosphorylation is known as substrate level phosphorylation.

Example The conversion of 1,3 bis phosphoglycerate to 3 phospho glycerate by the help of phospho glycerate kinase is an example of substrate level phosphorylation .

      In this reaction one phosphate moiety is being splited from 1,3 bis phosphoglycerate,the splited phosphate moiety then reacts with ADP to generate ATP.

i would say the prokaryotic cells the prokaryotic cells are less complex, are usually found only in unicellular organisms and have more limited capabilities than eukaryotic cells.

c: warm water flows from the western tropical pacific toward south america. that should be the right answer! hope it .