Antibodies, crucial for immune defense, are produced by:

Correct Answer: B

Rationale: Antibodies are produced by a specific type of lymphocyte known as B cells. B cells are a critical component of the adaptive immune system and are responsible for producing antibodies in response to pathogens. Neutrophils, monocytes, and basophils are types of white blood cells that are part of the innate immune response and do not have the function of producing antibodies. Neutrophils are primarily involved in phagocytosis, monocytes differentiate into macrophages and dendritic cells for antigen presentation, while basophils are involved in allergic reactions and parasitic infections.

Correct Answer: B

Rationale: Cartilage is a type of connective tissue that provides support and flexibility to various parts of the body, such as joints and the ear. It is composed of cells called chondrocytes embedded in a matrix of collagen and proteoglycans. Epithelial tissue covers body surfaces, muscle tissue is involved in movement, and nervous tissue transmits signals. The correct answer is connective tissue because cartilage serves a supportive function in the body.

Correct Answer: B

Rationale: Keratin is the correct answer as it is the hard, protective protein that comprises hair and nails. Collagen is a different type of protein found in connective tissues, providing structure and support. Elastin imparts elasticity to tissues, allowing them to stretch and recoil. Fibrin is a protein involved in the blood clotting process and is not related to the structure of hair and nails. Therefore, choices A, C, and D are incorrect in the context of the question.

Correct Answer: A

Rationale: The correct answer is A: Ligament. Ligaments are tough bands of tissue that connect bones to other bones at joints, providing stability and support. In the case of the wrist or ankle, ligaments play a crucial role in maintaining the structural integrity and allowing for proper movement of these joints. Tendons (option B) connect muscles to bones, not bones to bones. Fascia (option C) is a connective tissue that surrounds muscles and other structures, not connecting bones at joints. A synovial joint (option D) is a type of joint that allows for movement between bones, but it is not the flexible connection between bones at the wrist or ankle.

Correct Answer: A

Rationale: The relationship between wavelength (λ), frequency (f), and speed (v) of a wave is given by the formula λ = v / f. This formula is derived from the wave equation v = fλ, where v is the speed of the wave, f is the frequency, and λ is the wavelength. By rearranging the equation, we get λ = v / f, indicating that the wavelength is inversely proportional to the frequency when the speed of the wave is constant. Therefore, choice A, λ = v / f, correctly represents the relationship between wavelength and frequency when the speed of the wave is held constant. Choice B, λ = f / v, is incorrect because it represents an inverse relationship between wavelength and speed, which is not the case. Choice C, λ = vf, is incorrect as it implies a direct relationship between wavelength, frequency, and speed, which is not accurate. Choice D, λ is independent of f and v, is incorrect as both frequency and speed affect the wavelength of a wave, as shown by the correct formula λ = v / f.