Correct Answer: B

Rationale: Smooth muscles are the correct answer as they are found in the walls of hollow organs such as the intestines and blood vessels. Cardiac muscles are specifically found in the heart and are responsible for its contractions. Skeletal muscles are attached to bones and control voluntary movements. Voluntary muscles are under conscious control, but this term is not a specific type of muscle like smooth, cardiac, or skeletal muscles.

Correct Answer: B

Rationale: The correct answer is B: Red blood cell. Red blood cells, also known as erythrocytes, are responsible for carrying oxygen from the lungs to the body's tissues. They contain hemoglobin, a protein that binds to oxygen and transports it throughout the body. White blood cells (Choice A) are part of the immune system and help fight infections, not involved in carrying oxygen. Platelets (Choice C) are responsible for blood clotting, not oxygen transport. Plasma (Choice D) is the liquid component of blood that carries various substances like nutrients and waste products, but it does not directly carry oxygen.

Correct Answer: D

Rationale: Option D is the correct answer based on anatomical terms. The thumb is indeed located on the lateral aspect of the hand, following anatomical positioning. The terms 'proximal,' 'superior,' and 'inferior' are used in relation to the center of the body or a specific point of reference, while 'lateral' and 'medial' describe positions further away or closer to the midline of the body. Therefore, the thumb being on the lateral side of the hand is an accurate anatomical description. Choices A, B, and C are incorrect because they do not align with anatomical terminology. In anatomical terms, 'proximal' refers to a position closer to the center of the body, 'superior' indicates a position above or higher than another part, and 'inferior' signifies a position below or lower than another part. The shoulder joint is distal to the neck, the elbow is inferior to the shoulder, and the cervical vertebrae are superior to the thoracic vertebrae.

Correct Answer: A

Rationale: The correct answer is A: Ribosome. Ribosomes are the organelles responsible for protein synthesis in the cell. They are the cellular machinery where translation, the process of assembling proteins from amino acids based on mRNA sequences, occurs. Ribosomes can be found floating freely in the cytoplasm or attached to the endoplasmic reticulum. The nucleus (choice B) houses DNA but is not directly involved in protein synthesis. Mitochondria (choice C) are responsible for energy production through cellular respiration, not protein synthesis. The Golgi apparatus (choice D) is involved in modifying, sorting, and packaging proteins for secretion, not in the synthesis of proteins.

Correct Answer: A

Rationale: The correct answer is Estrogen (Choice A). Estrogen is produced by the ovaries and is essential for the maturation of eggs. It plays a crucial role in the development of secondary sexual characteristics, regulation of the menstrual cycle, and preparation of the uterus for implantation of a fertilized egg. Luteinizing Hormone (Choice B) is released by the pituitary gland and plays a role in ovulation, not the maturation of eggs. Progesterone (Choice C) is produced by the ovaries after ovulation and is important for preparing the uterus for pregnancy, not maturing eggs. Testosterone (Choice D) is a male sex hormone primarily produced in the testes, and while small amounts are also produced in the ovaries, it is not the hormone responsible for maturing eggs.