Correct Answer: B

Rationale: A gene is a portion of DNA that contains the instructions for a specific trait. Genotype refers to the genetic makeup of an organism, encompassing all its genes. Phenotype, on the other hand, is the observable physical manifestation resulting from the interaction between an organism's genotype and environmental factors. Choice A is incorrect because genes do not consist of amino acids directly; they are sequences of nucleotides. Choice C is incorrect as genes do not determine traits directly but provide the instructions for proteins that may influence traits. Choice D is incorrect as genes are not lipids, and lipids do not determine traits; they are a type of biomolecule with different functions.

Correct Answer: A

Rationale: The correct answer is A: The atomic number of an atom is the number of protons in its nucleus. This number uniquely identifies the element, as each element has a distinct number of protons. Neutrons and electrons play roles in the atom's structure and stability, but the atomic number specifically refers to the number of protons. Choice B (The number of neutrons in an atom) is incorrect because the atomic number does not include neutrons; it only represents the number of protons. Choice C (The number of electrons in an atom) is incorrect because the atomic number is not related to the number of electrons, which can vary in different atomic configurations. Choice D (The sum of protons and neutrons) is incorrect because it refers to the mass number of an atom, which is the total number of protons and neutrons in the nucleus, not just the protons.

Correct Answer: A

Rationale: The correct answer is A: Endocrine, parietal, chief, mucous cells. In the gastric glands of the stomach mucosa, the four types of cells are endocrine (producing hormones), parietal (secreting acid and intrinsic factor), chief (responsible for producing digestive enzymes), and mucous cells (providing protection to the stomach lining). These cells play essential roles in the digestive processes and maintaining the health of the stomach mucosa. Choices B, C, and D are incorrect because they do not accurately represent the types of cells found in the gastric glands of the stomach mucosa. Parietal cells secrete acid and intrinsic factor, chief cells produce digestive enzymes, and mucous cells provide protection, making these the correct choices in the context of gastric gland cellular composition.

Correct Answer: B

Rationale: The correct answer is B. Glial cells in the CNS include astrocytes, microglia, ependymal cells, and oligodendrocytes. Schwann cells and satellite cells are found in the PNS. Astrocytes are the most abundant type of glial cells and are involved in nutrient support, repair, and maintenance of the extracellular environment. Microglia are the resident immune cells of the CNS, playing a role in immune defense. Ependymal cells line the ventricles of the brain and the central canal of the spinal cord, contributing to the production and circulation of cerebrospinal fluid. Oligodendrocytes are responsible for producing myelin, which insulates axons in the CNS. Understanding the specific functions of each type of glial cell is essential in grasping the complexity of the central nervous system's support and protective mechanisms.

Correct Answer: B

Rationale: Sinusoidal capillaries are indeed the most permeable type. They are characterized by large gaps between endothelial cells, allowing for the passage of large molecules and cells. These capillaries are commonly found in organs like the liver, bone marrow, and spleen where high permeability is required for specialized functions such as filtration and exchange of substances. Continuous capillaries have tight junctions and are the least permeable, found in muscles, lungs, and the central nervous system where strict control over permeability is needed. Fenestrated capillaries, on the other hand, have small pores or fenestrations and are intermediate in permeability, found in organs like the kidneys, endocrine glands, and intestines where selective permeability is necessary. Vascular capillaries is not a specific type of capillary and is not a valid choice.