Questions

Cellular respiration is the multi-step process that creates energy from nutrients and food molecules. It begins in the cytoplasm of the cell, with the mitochondria functioning as the main organelle where the rest of the process continues and finishes.

During respiration, glycolysis occurs in the cytoplasm of the cell.

DNA is not a single stranded and does not have amino acids. Hence options, b & C are eiminated. Dna is a double helix structure containing nucleobase—either cytosine (C), guanine (G), adenine (A), or thymine (T)—as well as a monosaccharide sugar called deoxyribose and a phosphate group. 

To make steel, iron ore is first mined from the ground. It is then smelted in blast furnaces where the impurities are removed and carbon is added.

In simple, steel is iron alloyed with carbon, usually 0 - 2%.