Correct Answer: B

Rationale: A) Founder effect: This occurs when a small group of individuals establishes a new population, leading to a loss of genetic variation compared to the original population. It does not necessarily result in a gradual loss of genetic variation in an existing population. B) Bottleneck effect: This process occurs when a population is drastically reduced in size, leading to a significant loss of genetic variation due to the limited number of individuals contributing to the gene pool. The reduced genetic diversity can have long-term effects on the population's ability to adapt to environmental changes. C) Gene flow: This refers to the movement of genes between populations, which can introduce new genetic variation and prevent populations from diverging. Gene flow does not lead to a gradual loss of genetic variation within a population. D) Speciation: This is the process by which new species evolve from existing species, often involving the accumulation of genetic differences that l

Correct Answer: B

Rationale: The epidermis is the correct answer as it is the outermost layer of the skin, providing protection against pathogens and the environment. It consists of multiple layers, including the stratum corneum, which is the outermost layer of the epidermis. The dermis is located beneath the epidermis, offering structural support and housing blood vessels, nerves, and glands. The hypodermis is the deepest layer of the skin, made up of fat and connective tissue that secures the skin to underlying structures. Choice A, Dermis, is incorrect as it is located beneath the epidermis. Choice C, Hypodermis, is incorrect as it is the deepest layer of the skin, not the outermost. Choice D, Stratum corneum (part of the epidermis), is not the correct answer as it is a specific layer within the epidermis and not the overall outermost layer of the skin.

Correct Answer: C

Rationale: The main function of the urinary system is to maintain the body's acid-base balance. This is achieved by regulating the levels of electrolytes and water in the body. The kidneys filter waste products from the blood to form urine, which helps to regulate the pH balance. Choice A, transporting oxygen, is primarily the function of the respiratory system. Choice B, fighting off infections, is a function of the immune system. Therefore, the correct answer is maintaining acid-base balance.

Correct Answer: A

Rationale: Kwashiorkor is a severe acute malnutrition condition resulting from insufficient dietary protein intake. It is characterized by symptoms such as edema, skin lesions, an enlarged liver with fatty infiltrates, and notably, muscle wasting. Muscle wasting occurs as the body breaks down muscle tissue to obtain essential amino acids for vital functions. Night blindness (option B) is associated with vitamin A deficiency, scurvy (option C) results from a lack of vitamin C, and rickets (option D) is caused by a deficiency in vitamin D, calcium, or phosphate.

Correct Answer: B

Rationale: When unpolarized light passes through a polarizing filter, the filter only allows light waves oscillating in a specific direction to pass through while blocking light waves oscillating in other directions. Since unpolarized light consists of light waves oscillating in all possible directions, when it passes through a polarizing filter, only half of the light waves (those oscillating in the direction allowed by the filter) are transmitted. As a result, the intensity of the transmitted light is reduced by half. Choice A is incorrect because the light is not completely absorbed; choice C is incorrect because the polarizing filter affects the transmitted light; and choice D is incorrect because the intensity does not double, but rather decreases by half due to the selective transmission of light waves in a specific direction by the polarizing filter.