Correct Answer: B

Rationale: The correct answer is B: Create energy. The primary purpose of the mitochondria is to generate energy for the cell. Mitochondria are known as the 'powerhouses' of the cell because they produce ATP (adenosine triphosphate), which is the energy currency used by cells to carry out various functions and processes.
Choice A is incorrect as the mitochondria do not control the cell but rather produce energy.
Choice C is incorrect as protein synthesis primarily occurs in the ribosomes.
Choice D is incorrect as packaging waste for removal is a function associated with lysosomes, not mitochondria.

Correct Answer: A

Rationale: The nucleus is important in a cell because it stores the DNA, which contains the genetic information necessary for the cell's function and replication. This genetic material controls the cell's activities and characteristics.

Choices B, C, and D are incorrect because supporting the cell, making proteins, and producing energy are functions typically associated with other cell organelles like the cytoskeleton, ribosomes, and mitochondria, respectively.

Correct Answer: B

Rationale: The correct answer is B: Carrier proteins. Carrier proteins are involved in facilitated diffusion, a type of passive transport where specific target molecules are moved across the membrane with the help of proteins that change shape. These carrier proteins bind to the target molecule on one side of the membrane, undergo a conformational change, and then release the molecule on the other side. This process is crucial for the selective transport of certain molecules that cannot pass through the membrane by simple diffusion.

Choices A and C are incorrect because diffusion and channel proteins do not involve proteins that change shape to transport target molecules selectively.
Choice D is incorrect as carrier proteins fit the description provided in the question.

Correct Answer: D

Rationale: The endocrine system comprises a network of glands that produce and release hormones to regulate bodily functions. The pituitary gland, thyroid gland, and adrenal glands are essential components of this system. The pituitary gland secretes various hormones that control other glands and some body functions. The thyroid gland regulates metabolism, growth, and energy levels by producing thyroid hormones. The adrenal glands produce hormones involved in stress response, metabolism, and immune function.
Therefore, all of the above glands are integral parts of the endocrine system, making choice D the correct answer.

Correct Answer: C

Rationale: Metabolism is the sum of all chemical reactions that occur within an organism to maintain life. It involves all the processes that break down molecules to release energy (catabolism) and build new molecules to support growth and maintenance (anabolism). Respiration refers specifically to the process of generating energy from the breakdown of glucose molecules. Synthesis is the creation of complex molecules from simpler ones.
Therefore, metabolism is the most comprehensive term that encompasses all these processes within an organism.