Mometrix TEAS 7 science practice test

Correct Answer: B

Rationale: Calcium phosphate is the main component that gives bones their rigidity and hardness. It combines with calcium hydroxide to form hydroxyapatite crystals, which provide strength and structure to bones. Collagen, on the other hand, provides flexibility and tensile strength. Cartilage is a type of connective tissue found in joints, and ligaments are fibrous tissues that connect bones to other bones, but they do not contribute to the rigidity and hardness of bones.

Correct Answer: B

Rationale: The nucleus is the organelle that contains the genetic material (DNA) of the cell. It acts as the control center of the cell, regulating gene expression and coordinating cellular activities. The cytoplasm is the fluid-filled space within the cell where organelles are suspended, but it does not contain the genetic material. The cell wall is a rigid structure found in plant cells that provides support and protection, but it does not house the DNA. The Golgi apparatus is involved in processing and packaging proteins for secretion, but it does not contain the genetic material of the cell.

Correct Answer: A

Rationale: The main difference between a telescope and a microscope lies in their primary functions. Telescopes are specifically designed to magnify and observe distant objects like stars, planets, and galaxies, making them essential tools for astronomy. In contrast, microscopes are utilized to magnify and study small objects such as cells, bacteria, and other microscopic organisms in fields like biology and medicine. Therefore, the key distinction is that telescopes focus on magnifying distant objects, while microscopes are tailored for magnifying small objects. Choice B is incorrect because while some microscopes may use mirrors in certain designs, the primary component is typically lenses. Choice C is incorrect as telescopes collect and focus light for observation, while microscopes use light to illuminate and magnify objects. Choice D is incorrect because while both instruments magnify objects, their main purposes and the types of objects they focus on are distinctly different.

Correct Answer: C

Rationale: In the absence of air resistance, both balls will experience the same acceleration due to gravity (9.8 m/s^2) regardless of their densities or materials. This means that both balls will reach the ground at the same time, assuming they are dropped from the same height simultaneously. The differences in density or material composition do not affect the rate at which objects fall in a vacuum. Therefore, both the clay and steel balls, being identical in shape and starting position, will have the same free-fall acceleration and will hit the ground simultaneously. Choices A and B are incorrect because the density of the materials does not impact the time it takes for objects to fall under gravity alone. Choice D is incorrect as the initial velocities do not play a role in the time taken to fall in a vacuum, where only the acceleration due to gravity affects the motion.

Correct Answer: A

Rationale: - The majority of the body's immune cells are located in the blood. Immune cells, such as white blood cells (leukocytes), circulate throughout the body via the bloodstream to detect and fight off infections and foreign invaders. - While immune cells are also present in other parts of the body like the lymph nodes, spleen, and bone marrow, the blood serves as a primary conduit for immune cells to travel to different tissues and organs to carry out their functions. - The brain (option B) is protected by the blood-brain barrier, which limits the entry of immune cells into the brain to prevent inflammation and damage. - The skin (option C) contains immune cells like Langerhans cells that help protect against pathogens, but the largest concentration of immune cells is found in the blood. - The large intestine (option D) also houses a significant amount of immune cells due to its role in interacting with the external environment through the gut-associated lymphoid tissue, but the primary location for most of the body's immune cells is the blood.