Which of the following is an example of a fibrous protein?

Correct Answer: D

Rationale: A) Insulin is a hormone, not a fibrous protein. It is produced in the pancreas and regulates blood sugar levels. B) Keratin is a fibrous structural protein found in hair, nails, and the outer skin layer, providing strength and protection. C) Hemoglobin is a globular protein in red blood cells responsible for oxygen transport; it is not fibrous. D) Collagen is a fibrous protein found in tendons, ligaments, and skin, offering strength and structure to connective tissues. Therefore, the correct answer is collagen, making it the main component of various connective tissues.

Correct Answer: C

Rationale: Work is defined as the product of the force applied to an object and the distance over which the force is applied. In the situation of lifting a box to place it on a shelf, work is being done on the object. This is because lifting the box involves applying a force over a distance (the height of the shelf). The force applied to lift the box results in work being done on the object by raising it against the force of gravity. Choices A, B, and D do not involve work being done on the object as they either do not involve movement against a force (A, D) or do not cover distance against a force (B).

Correct Answer: C

Rationale: Power is the rate at which work is done or energy is transferred. The unit of measurement for power is the watt (W), named after James Watt, the inventor of the steam engine. The watt is defined as one joule per second, where a joule (J) is the unit of energy. Choice A, Joule (J), is incorrect because a joule is a unit of energy, not power. Choice B, Newton (N), is incorrect as a Newton is a unit of force, not power. Choice D, Kilogram-meter (kg·m), is incorrect as it represents a unit of torque, not power. Therefore, the correct answer is C: Watt (W).

Correct Answer: A

Rationale: The correct answer is A: Neuron. Neurons are the fundamental building blocks of the nervous system. These specialized cells play a crucial role in transmitting information through electrical and chemical signals. While nerves are comprised of bundles of neurons and ganglia consist of clusters of nerve cell bodies located outside the central nervous system, neuroglia serve as support cells for neurons. Neurons are specifically responsible for processing and transmitting information within the nervous system, making them the essential unit of this complex system. Choices B, C, and D are incorrect as nerves are bundles of neurons, ganglia are clusters of nerve cell bodies outside the central nervous system, and neuroglia are support cells for neurons, not the fundamental units responsible for information processing and transmission.

Correct Answer: B

Rationale: Gravitational potential energy is directly proportional to the height or distance from the ground. As the object is raised higher, its gravitational potential energy increases. While the mass of the object influences gravitational potential energy, the distance from the ground has a more significant impact on it. The gravitational force does not directly affect the gravitational potential energy; it is the force that causes the potential energy to change with height. The shape of the object also does not determine gravitational potential energy, as it is primarily determined by the object's position in a gravitational field.