Classifications of human tissues exclude:

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: 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.

Correct Answer: D

Rationale: During embryonic development, all tissues originate from the three primary germ layers: ectoderm, mesoderm, and endoderm. These germ layers give rise to various tissues and organs in the developing embryo through a process called gastrulation. Epithelial, muscle, and connective tissues are derived from these germ layers during development. Therefore, choices A, B, and C are incorrect as tissues do not originate from a single type of tissue but rather from the embryonic germ layers which differentiate into various tissues and organs.

Correct Answer: C

Rationale: Sweat glands play a vital role in regulating body temperature by releasing a watery fluid that evaporates from the skin's surface. This evaporation process helps cool the body down by dissipating heat, which is essential for maintaining a stable internal temperature. Choice A is incorrect because sweat glands do not produce sebum but rather a watery fluid. Choice B is incorrect because sweating itself does not involve the constriction of blood vessels; instead, it promotes heat loss through evaporation. Choice D is incorrect as sweat glands do not thicken the epidermis for insulation but rather facilitate the cooling process through sweat evaporation.