What are the three layers of the skin?

Correct Answer: B

Rationale: The correct answer is B: Epidermis, dermis, hypodermis. The three layers of the skin are the epidermis (outer layer), dermis (middle layer), and hypodermis (inner layer of fat and connective tissue). The hypodermis is also known as the subcutaneous tissue and is primarily composed of adipose (fat) tissue, providing insulation and padding to the body. Choice A is incorrect as 'subdermis' is not a recognized layer of the skin. Choice C is incorrect as 'dermis' is the middle layer, not the outer layer. Choice D is incorrect as the layer below the dermis is the hypodermis, not specifically an 'adipose layer.'

Correct Answer: D

Rationale: An isotope of an element is an atom with a different number of neutrons, resulting in a different mass number. Isotopes of the same element have the same number of protons (which determines the element's identity) but differ in the number of neutrons, leading to variations in mass numbers. Choice A is incorrect because isotopes of the same element have the same atomic number. Choice B is incorrect because isotopes of the same element have the same number of protons. Choice C is incorrect because isotopes of the same element have the same number of electrons.

Correct Answer: C

Rationale: The correct answer is C. The large intestine absorbs water, vitamin K, bile salts, sodium, and chloride ions. It helps in maintaining the body's water and electrolyte balance, and also plays a role in absorbing certain vitamins and nutrients such as vitamin K. Choices A, B, and D are incorrect because proteins, carbohydrates, vitamins A, D, E, and K are primarily absorbed in the small intestine, not the large intestine.

Correct Answer: B

Rationale: Lipids are hydrophobic molecules that are soluble in nonpolar solvents like oils but insoluble in water. They consist of fats, oils, waxes, and steroids and play essential roles in energy storage, insulation, and cell membrane structure. Carbohydrates, proteins, and nucleic acids are not typically soluble in nonpolar solvents and do not exhibit the same hydrophobic characteristics as lipids. Carbohydrates are usually hydrophilic and soluble in water, proteins have both hydrophilic and hydrophobic regions but are not generally soluble in nonpolar solvents, and nucleic acids are polar molecules that are not known for their solubility in nonpolar solvents.

Correct Answer: A

Rationale: The correct answer is A: Lag, exponential, stationary, death. The phases of bacterial growth start with the lag phase where bacteria acclimate to their environment, followed by the exponential phase characterized by rapid growth. This is then followed by the stationary phase where growth slows as resources deplete, and finally, the death phase where the population declines. Choice B is incorrect as it has the order of phases mixed up. Choice C is incorrect as it also has the order of phases mixed up. Choice D is incorrect as it has the stationary phase occurring before the exponential phase, which is inaccurate.

Correct Answer: D

Rationale: Human cells typically contain genes that code for proteins necessary for the cell's functions. DNA that codes for proteins the cell doesn't use would be an inefficient use of the cell's resources. Therefore, it is less likely to be found in a human cell's genes. Options A, B, and C are more commonly associated with genes found in human cells. Choice A refers to the genetic information needed for protein synthesis, while choice B involves traits that can be present in the gene pool. Mutated DNA (choice C) can also be found in human cells as a result of genetic alterations. However, DNA that codes for proteins not utilized by the cell would be redundant and not typically retained in the genome.

Correct Answer: C

Rationale: In this scenario, where a child complains of heavy breathing even when relaxing and has no history of respiratory problems, the most likely issue is hyperventilation. Hyperventilation is an abnormal breathing pattern where a person breathes in excess of the body's requirements. It can be triggered by stress, anxiety, panic attacks, or lower-than-normal carbon dioxide levels in the blood. Unlike asthma, a blood clot, or exercising too hard, hyperventilation fits the symptoms described and is more common in individuals without a history of respiratory problems.

Correct Answer: A

Rationale: The correct answer is A: Continuous, fenestrated, sinusoidal. Capillaries are classified into three types based on their permeability: continuous (least permeable), fenestrated (moderately permeable), and sinusoidal (most permeable). Choices B, C, and D are incorrect because they do not represent the three main types of capillaries. Choice B includes 'discontinuous' which is not a recognized type. Choice C includes 'alveolar' which is not a type of capillary, and Choice D includes 'vascular' which is too broad and not specific to capillary classification.

Correct Answer: B

Rationale: Accuracy refers to how close a measurement is to the true or accepted value, while precision refers to how close individual measurements are to each other. If the measurements are accurate but not precise, it means they consistently hit the target value but may vary in terms of how closely grouped they are. Choice B, 'They are accurate but not precise,' correctly describes the scenario where the measurements are on target but not consistently close to each other. Choice A is incorrect because it implies both accuracy and precision, which is not the case here. Choice C is incorrect because it suggests precision without accuracy, while choice D is incorrect as it indicates neither accuracy nor precision, which is not a typical scenario for measurements.