Answer: C) Mitochondria Explanation: 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.

(A) Keratin

Hair is primarily composed of a protein called keratin. Keratin is a fibrous structural protein that forms the main component of hair, as well as nails and the outer layer of the skin. It provides strength and resilience to these structures. The other options—Casein, Globulin, and Mucin—are proteins found in other parts of the body and have different functions.

Answer: B) They are the sites at which microtubules attach to chromosomes. Explanation: They are the sites at which microtubules attach to chromosomes.

Answer: A) taking in carbon dioxide and making carbohydrates (sugars) Explanation: Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can later be released to fuel the organisms activities.

Answer: A) Chloroplasts Explanation: Chloroplasts contains chlorophyll, the green substance in plants that allows them to create food from carbon dioxide and water called as photosynthesis.