What is the process of converting ammonia, a byproduct of protein digestion, into a less toxic form?

Correct Answer: A

Rationale: Deamination is the correct answer. It is the process of removing an amino group from a molecule, like converting ammonia (NH3) into a less toxic form such as urea. Ammonia, a byproduct of protein digestion, must be converted into a less toxic form for excretion. Deamination is a crucial step that mainly occurs in the liver through the urea cycle. Transamination involves transferring an amino group from one molecule to another, not removing it as in deamination. Decarboxylation is the removal of a carboxyl group from a molecule, and hydrolysis is the breakdown of a compound by adding water.

Correct Answer: C

Rationale: Reactivity refers to a substance's ability to undergo a change that transforms it into a different substance through a chemical reaction. In this context, reactivity specifically refers to the chemical behavior of a substance. Density, mass, and volume are physical properties of a substance and do not describe its ability to undergo a chemical change. Density is the mass per unit volume, mass is the amount of matter in an object, and volume is the amount of space occupied by an object. Therefore, reactivity is the most appropriate term to describe a substance's ability to undergo a transformation into a different substance.

Correct Answer: C

Rationale: Cartilage is a type of connective tissue that provides flexible support in various structures. Ears, joints, and the nose all contain cartilage. Muscles, however, are made up of muscle tissue, not cartilage. Therefore, muscles do not contain cartilage. Choice A, ears, choice B, joints, and choice D, nose, are incorrect as they all contain cartilage. Choice C, muscles, is the correct answer as muscles are not composed of cartilage.

Correct Answer: A

Rationale: In the sentence 'He gave his mother a bouquet of flowers,' the indirect object is 'his mother' because she is the recipient of the action of giving. The direct object is 'a bouquet of flowers' because it is the thing being given. The verb 'gave' is the action being performed. Choice B, 'bouquet,' is incorrect as it is the direct object, not the indirect object. Choice C, 'flowers,' is incorrect as it is part of the direct object phrase. Choice D, 'gave,' is incorrect as it is the verb indicating the action, not an object.

Correct Answer: B

Rationale: The correct answer is B, Cardiac muscle. Cardiac muscle is the type of muscle tissue that has a unique branching network and is found in the heart. This type of muscle is involuntary and contracts rhythmically to pump blood throughout the body. Skeletal muscle, choice A, is attached to bones and is responsible for voluntary movements. Smooth muscle, choice C, is found in the walls of internal organs and blood vessels, playing a role in involuntary movements. Multifidus muscle, choice D, is a specific muscle in the back that helps with spinal stability, unrelated to the unique branching network found in cardiac muscle.

Correct Answer: B

Rationale: When an object is compressed, its potential energy increases. This is because work is done on the object to compress it, resulting in an increase in potential energy stored in the object as it is compressed against an opposing force. The potential energy is transformed and stored within the object due to the work done during the compression process, leading to an increase in its potential energy. Choice A is incorrect because compression involves doing work on the object, increasing its potential energy. Choice C is incorrect because compression involves a change in position and potential energy. Choice D is incorrect because compression does not reduce potential energy to zero; rather, it increases it due to the work done in compressing the object.

Correct Answer: B

Rationale: When the temperature of a gas increases at constant pressure, the average kinetic energy of the gas molecules increases. This leads to the gas molecules moving faster and spreading out more, which causes them to occupy a larger volume. As a result, the density of the gas decreases because the same number of gas molecules are now distributed over a larger space. Choice A is incorrect because as the gas molecules spread out, the density decreases. Choice C is incorrect because the increase in temperature leads to a decrease in density due to the increased volume occupied by the gas molecules. Choice D is incorrect because with the provided scenario of temperature increase at constant pressure, the effect on density can be determined.

Correct Answer: C

Rationale: The epiglottis plays a crucial role during swallowing by covering the trachea to prevent food or liquid from entering the airway, which could lead to aspiration. By acting as a lid over the trachea, it ensures that food passes down the esophagus to the stomach, preventing it from entering the lungs. Choice A is incorrect as the swallowing reflex is a coordinated muscular action involving the tongue and throat muscles. Choice B is incorrect as grinding food into smaller pieces is primarily the function of the teeth and the initial stages of digestion. Choice D is incorrect as the storage of saliva for lubrication is not a function of the epiglottis, but rather involves salivary glands.

Correct Answer: B

Rationale: Endocrine glands release hormones directly into the bloodstream without the use of ducts. This allows the hormones to be distributed throughout the body to target organs or tissues. Exocrine glands, on the contrary, release their secretions through ducts to the external environment or onto a surface, such as sweat glands. Apocrine and merocrine glands are both types of exocrine glands that release their secretions through different mechanisms. Apocrine glands release their secretions along with portions of the cell itself, while merocrine glands release their secretions through exocytosis without loss of cellular material.