ATI TEAS Practice Test Science

Correct Answer: B

Rationale: The correct answer is B: Kidneys. The kidneys play a vital role in filtering waste from the blood, regulating fluid and electrolyte balance in the body. The liver is involved in detoxification and metabolism, while the pancreas aids in digestion and blood sugar regulation. The heart is responsible for pumping blood throughout the body and does not directly filter waste from the blood.

Correct Answer: B

Rationale: The correct answer is B. Fats are primarily digested in the small intestine, where bile from the liver emulsifies fats for enzymatic digestion. The small intestine is where most of the absorption of nutrients occurs. Proteins, on the other hand, are mainly digested in the stomach by the enzyme pepsin under acidic conditions. The stomach's acidic environment helps denature proteins, making them more accessible to pepsin for digestion. Choices A, C, and D are incorrect because they do not accurately reflect the primary sites of fat and protein digestion in the human digestive system.

Correct Answer: A

Rationale: Hydroxyapatite is a mineral compound composed of calcium and phosphorus that plays a crucial role in strengthening the collagen matrix of bones, contributing to their structural integrity and hardness. It is a key component of bone tissue and provides the mineralization necessary for bone strength and density. Choice B is incorrect because the structural unit of a bone is the osteon or Haversian system, not hydroxyapatite. Choice C is incorrect as it describes cartilage, not hydroxyapatite. Choice D is incorrect as it refers to the epiphysis, which is not synonymous with hydroxyapatite.

Correct Answer: B

Rationale: The correct term for a microorganism that lives on or in the human body without causing harm is a commensal microorganism. Commensal microorganisms coexist with the host without causing disease or harm. Choice A, 'Bacteria,' is too broad as not all bacteria are harmless in the body. Choice C, 'Microorganism,' is a general term and does not specifically refer to the harmless nature of the organism. Choice D, 'Host,' refers to the organism harboring the microorganism, not the microorganism itself.

Correct Answer: A

Rationale: The correct answer is the Thymus. T-cells mature and develop their receptors in the thymus gland, making it a vital organ for the immune system. The thymus provides the necessary environment for T-cells to differentiate and acquire their specific receptors and functions, which are essential for their role in the adaptive immune response. The spleen, lymph nodes, and bone marrow are all important components of the immune system, but they do not primarily serve as sites for T-cell maturation and T-cell receptor production.