After the Industrial Revolution, the population of peppered moths in England shifted towards more dark moths. This is an example of:

Correct Answer: B

Rationale: The shift in the peppered moth population towards more dark moths in England after the Industrial Revolution exemplifies natural selection acting on pre-existing variation. Initially, light-colored moths were well-camouflaged against lichen-covered tree trunks, but with industrial pollution darkening the tree trunks, dark-colored moths gained a survival advantage. This change reflects how the environment favored dark moths over light ones, illustrating natural selection. The process illustrates how organisms with traits advantageous in a changing environment are more likely to survive and reproduce, leading to the prevalence of those traits in the population over time. The choices of artificial selection (A), punctuated equilibrium (C), and Lamarckism (D) are not applicable in this scenario. Artificial selection involves intentional breeding by humans, punctuated equilibrium refers to rapid bursts of evolution followed by periods of stability, and Lamarckism suggests the inheritance of acquired characteristics, none of which align with the observed shift in moth populations based on environmental changes.

Correct Answer: B

Rationale: The skeletal system consists of bones, cartilage, ligaments, and tendons that work together to provide structure, support, protection for internal organs, and facilitate movement. It is responsible for supporting the body's framework and protecting vital organs. The muscular system (option A) consists of muscles that work with the skeletal system to produce movement but does not include bones, cartilage, ligaments, and tendons. The nervous system (option C) is responsible for transmitting signals throughout the body to control movement and other functions. The endocrine system (option D) is a collection of glands that produce hormones to regulate various bodily functions but is not primarily involved in structure, support, and movement as the skeletal system is.

Correct Answer: A

Rationale: The correct answer is A: Ribosomes. Ribosomes are the organelles responsible for protein synthesis in the cell. They can be found either freely floating in the cytoplasm or attached to the endoplasmic reticulum. The Golgi apparatus (Choice B) is involved in processing and packaging proteins, not protein production. Mitochondria (Choice C) are responsible for energy production, not protein synthesis. Lysosomes (Choice D) are involved in digestion and waste removal, not protein production.

Correct Answer: C

Rationale: The correct answer is C: Selective passage of materials. Tight junctions act as specialized structures between animal cells that create a barrier to the passage of materials. Their primary function is to prevent the leakage of extracellular fluid and control the selective passage of molecules between cells. This selective control is crucial in regulating the movement of substances across cell layers. Tight junctions do not directly facilitate communication between cells or provide anchorage between cells, as their main role is to regulate the passage of materials. Choices A and B are incorrect as tight junctions do not primarily serve for communication or anchorage between cells.

Correct Answer: B

Rationale: Bone is composed of connective tissue. Connective tissues are characterized by having cells scattered within an extracellular matrix. In the case of bone, the extracellular matrix is mineralized, giving bone its hardness and strength. Choice A, epithelial tissue, is not correct as bone is not primarily composed of epithelial cells. Choice C, hard connective tissue, is not a recognized category of tissue in the scientific classification; bone is classified under connective tissue. Choice D, muscle tissue, is incorrect as bone and muscle tissues are distinct types of tissues with different structures and functions.