Correct Answer: A

Rationale: Cell division is the correct answer. It is the process by which a parent cell divides into two or more daughter cells, enabling growth, repair, and reproduction in living organisms. This process ensures that genetic material is accurately passed on to the new cells. Cell differentiation refers to the specialization of cells to perform specific functions, while cell growth is the increase in size or mass of a cell. Cell regeneration involves replacing damaged or lost cells with new ones, where cell division plays a role but is not the primary process of generating new cells.
Therefore, in the context of cells producing new cells, cell division is the accurate term.

Correct Answer: A

Rationale: Stomach acid, also known as gastric acid, is primarily composed of hydrochloric acid. Hydrochloric acid plays a crucial role in the digestive process by helping to break down food and kill bacteria in the stomach. Bicarbonate is a base that helps neutralize stomach acid in the small intestine, but it is not the main component of stomach acid. Bile salts are produced by the liver and stored in the gallbladder, aiding in the digestion and absorption of fats, but they are not the main component of stomach acid. Enzymes are proteins that help catalyze chemical reactions in the body, including the breakdown of food molecules during digestion, but they are not the main component of stomach acid.

Correct Answer: B

Rationale: The normal force from the floor is perpendicular to the direction of motion of the box, so it does not contribute to the work being done. Work is only done by forces acting in the direction of motion of an object. In this case, the normal force is acting at a right angle to the motion, hence it does not perform any work on the box. The person's pushing force, the gravitational force, and the frictional force are all acting in the direction of motion of the box, so they contribute to the work being done in moving the box across the floor.

Correct Answer: A

Rationale: Phagocytes are a type of white blood cell that plays a crucial role in the immune system by engulfing and digesting foreign invaders such as bacteria, viruses, and other harmful substances. They are part of the body's innate immune response and are essential for protecting the body against infections. Lymphocytes, on the other hand, are another type of white blood cell involved in the adaptive immune response, producing antibodies, and coordinating immune responses. Platelets are cell fragments involved in blood clotting, while red blood cells are responsible for carrying oxygen to tissues.
Therefore, the correct answer is Phagocytes (
Choice
A) because they are specifically tasked with attacking and destroying foreign invaders in the body, distinguishing them from the other choices which have different functions within the immune system.

Correct Answer: A

Rationale: A ball-and-socket joint allows for the most movement among the options provided. This type of joint is characterized by a rounded end of one bone fitting into a cup-like socket of another bone, allowing for a wide range of motion in multiple directions. The shoulder joint is a prime example of a ball-and-socket joint, enabling movements such as flexion, extension, abduction, adduction, and rotation. In contrast, a hinge joint (option
B) like the elbow primarily allows for movement in one plane (flexion and extension). Fibrocartilaginous joints (option
C) like the wrists have limited movement due to the presence of cartilage between the bones. Suture joints (option
D) in the skull are immovable joints that provide structural support but do not allow for significant movement.