TEAS 7 science study guide free

Correct Answer: A

Rationale: Parathyroid hormone (PTH) is the correct answer. PTH stimulates the release of calcium from bones, leading to increased blood calcium levels. It acts on the bones to release calcium into the bloodstream, facilitates the kidneys' reabsorption of calcium, and triggers vitamin D activation to boost calcium absorption from the intestines. Choice B, Calcitonin, is incorrect as it works in opposition to PTH by decreasing blood calcium levels through inhibiting calcium release from bones. Choices C and D, Growth hormone and Testosterone, are not directly involved in calcium homeostasis and do not regulate blood calcium levels through bone calcium release mechanisms.

Correct Answer: D

Rationale: Velocity is a vector quantity as it encompasses both magnitude (speed) and direction. When describing the motion of an object, it is crucial to consider both aspects. Speed (option A) is a scalar quantity, representing only the magnitude of motion without indicating direction. Distance (option B) is also a scalar quantity, indicating the extent of an object's motion without considering direction. Mass (option C) is a scalar quantity, measuring the amount of matter in an object and not involving direction.

Correct Answer: A

Rationale: The correct answer is A: Myelin sheath. The myelin sheath is a fatty layer that surrounds and insulates some nerve fibers, facilitating the rapid transmission of signals along the nerve fibers. Choices B, C, and D (Dura mater, Pia mater, and Arachnoid mater) are layers of the meninges, protective membranes that surround the brain and spinal cord. The primary function of the meninges is to protect and support the central nervous system, not to insulate nerve fibers for signal transmission.

Correct Answer: C

Rationale: The centripetal force is the force responsible for keeping an object moving in a circular path. It is directed towards the center of the circle, providing the necessary inward acceleration to maintain the object's curved trajectory. Without this force, the object would move in a straight line tangent to the circle. Tension force, frictional force, and gravitational force are not the forces that cause an object to move in a circular path. Tension force is typically present in a string or rope and acts along the length of the material. Frictional force opposes the motion of an object relative to a surface, and gravitational force is the force of attraction between two masses.

Correct Answer: D

Rationale: The correct answer is D: Mouth. The mouth is the organ that helps break down food by grinding it with your teeth. The process of chewing, also known as mastication, breaks down food into smaller pieces, making it easier to swallow and digest. The teeth in the mouth play a crucial role in this initial stage of digestion by physically breaking down food into smaller particles. The other options listed, such as the stomach, esophagus, and liver, do not directly participate in the mechanical breakdown of food through chewing. The stomach is responsible for further digestion through chemical processes, the esophagus is a muscular tube that helps transport food to the stomach, and the liver is primarily involved in metabolic functions and bile production.