A ball is thrown horizontally off a cliff. Which of the following forces is responsible for its downward motion?

Correct Answer: D

Rationale: The gravitational force is responsible for the downward motion of the ball. When the ball is thrown horizontally off a cliff, the only force acting on it in the vertical direction is the force of gravity, which pulls the ball downward towards the ground. The other forces mentioned (force of throwing, normal force from the air, tension force from the string) do not contribute to the ball's downward motion in this scenario. The force of throwing initiates the horizontal motion, the normal force from the air opposes the ball's motion through air resistance, and tension force from the string would only be relevant if a string were attached to the ball. Therefore, gravitational force is the primary force responsible for the ball's downward motion in this situation.

Correct Answer: D

Rationale: The correct answer is D: Bony tissue. Classifications of human tissues typically include epithelial tissue, nervous tissue, and connective tissue types such as adipose tissue. Bony tissue, also known as bone tissue, is a specialized form of connective tissue that provides structural support and protection for the body. Therefore, it is not excluded from classifications of human tissues. Choices A, B, and C are valid types of human tissues and are correctly included in classifications of human tissues.

Correct Answer: C

Rationale: The correct answer is the pancreas. The hormone responsible for regulating blood sugar levels is insulin, which is produced by the pancreas. The pituitary gland produces various hormones that regulate other endocrine glands, the thyroid gland produces hormones that regulate metabolism, and the adrenal glands produce hormones involved in the stress response. Therefore, choices A, B, and D are incorrect in the context of regulating blood sugar levels.

Correct Answer: D

Rationale: The correct answer is D: Eukaryotic cells have a true nucleus and membrane-bound organelles, while prokaryotic cells lack these. This is because eukaryotic cells are more complex and organized compared to prokaryotic cells. Eukaryotic cells have a well-defined nucleus that houses the genetic material, as well as various membrane-bound organelles such as mitochondria, endoplasmic reticulum, and Golgi apparatus, each performing specific functions within the cell. Option A is incorrect because prokaryotic cells lack a true nucleus; instead, they have a nucleoid region where the genetic material is found. Option B is incorrect as eukaryotic cells are actually more complex in structure compared to prokaryotic cells. Option C is incorrect because prokaryotic cells do not have membrane-bound organelles like eukaryotic cells do. Understanding the distinction between prokaryotic and eukaryotic cells is fundamental in the field of anatomy and biology. This knowledge is crucial for students to comprehend the structural and functional differences between different types of cells, which forms the basis of understanding more advanced biological concepts.

Correct Answer: C

Rationale: The correct answer is 'Cellulose.' Cellulose is the main component of the cell wall in plant cells, providing structural support and rigidity. Starch, while a carbohydrate, is a storage form of glucose in plants and not a component of the cell wall. Glucose is a simple sugar that can be used as an energy source but is not the main component of the cell wall. Chitin is a structural carbohydrate found in the exoskeleton of arthropods and fungi, not in plant cell walls.