Correct Answer: C

Rationale: Sarcomeres are the smallest contractile units within muscle cells. They consist of overlapping filaments of actin and myosin proteins, which interact to produce muscle contractions. Myocytes are the entire muscle cells, myofibrils are bundles of protein filaments found within muscle cells, and tendons are tough connective tissues that connect muscles to bones. Therefore, sarcomeres specifically represent the contractile units responsible for muscle contraction, making them the correct answer in this context.

Correct Answer: D

Rationale: The reticular formation is a network of neurons located in the brainstem that plays a crucial role in regulating sleep-wake cycles, coordinating various sensory inputs, and maintaining wakefulness. It acts as a filter for incoming sensory information and helps in directing attention to important stimuli. The other options, the cerebrum, hypothalamus, and medulla oblongata, are important structures in the brain but are not primarily responsible for the specific functions mentioned in the question. The cerebrum is mainly involved in higher brain functions such as thinking and voluntary movements. The hypothalamus is responsible for regulating body temperature, hunger, and thirst, among other functions. The medulla oblongata is essential for controlling vital autonomic functions like breathing and heart rate.

Correct Answer: A

Rationale: The wavelength of a wave represents the distance between two successive identical points on a wave, such as two crests or two troughs. It is typically measured in meters and is a fundamental characteristic of a wave, influencing its properties and behavior. Wavelength is crucial in wave physics, affecting phenomena like interference, diffraction, and the wave's speed in a medium. Amplitude refers to the maximum displacement of a wave from its rest position, frequency is the number of complete oscillations a wave makes in a given time, and period is the time it takes for a wave to complete one full cycle. These properties are different from wavelength and serve distinct purposes in describing waves.

Correct Answer: C

Rationale: The primary function of the ovaries in the female reproductive system is to produce eggs (ova). Ovaries are responsible for the production of female gametes. Additionally, they secrete hormones such as estrogen and progesterone, which are essential for the menstrual cycle and pregnancy. Transporting sperm to the uterus is the function of the fallopian tubes, not the ovaries. Producing milk for feeding offspring is the role of the mammary glands, not the ovaries. Regulating urination is a function associated with the urinary system, not the female reproductive system or the ovaries.

Correct Answer: D

Rationale: Ribosomes are cellular organelles responsible for protein synthesis. They read the genetic information encoded in messenger RNA (mRNA) and use this information to assemble amino acids into a specific sequence, forming a protein. This process is known as translation and is essential for the production of proteins that carry out various functions in the cell. Options A, B, and C are incorrect as they do not accurately describe the primary function of ribosomes. Choice A is incorrect because the synthesis of lipids and other cellular components is not the primary function of ribosomes. Choice B is incorrect as packaging and transporting proteins are functions typically associated with the endoplasmic reticulum and Golgi apparatus. Choice C is incorrect because ribosomes do not break down macromolecules; instead, they are involved in building proteins from amino acids.