Correct Answer: D

Rationale: Bases are substances that can accept protons or donate hydroxide ions in a chemical reaction. One common property of bases is that they turn red litmus paper blue. This is a classic test to distinguish between acids (which turn blue litmus paper red) and bases. Conductivity in aqueous solutions (Option A) is a property of both acids and bases, but not unique to bases alone. Sour taste (Option B) is a property commonly associated with acids, not bases. Reactivity with metals to produce hydrogen gas (Option C) is a property of acids, particularly strong acids, but not bases.

Correct Answer: B

Rationale: Implantation is the correct answer. It is the process where a fertilized egg attaches itself to the lining of the uterus to establish a pregnancy. Fertilization is the initial step where the sperm and egg fuse to form a zygote. Gestation refers to the period of fetal development within the uterus. Parturition is the process of giving birth and is not related to the implantation of the fertilized egg, which occurs earlier in the reproductive process.

Correct Answer: A

Rationale: In a neutral atom, the number of electrons must be equal to the number of protons to maintain electrical neutrality. Electrons carry a negative charge while protons carry a positive charge. By having an equal number of electrons and protons, the positive and negative charges balance each other out, resulting in an electrically neutral atom. Choice B is incorrect because in a neutral atom, the number of electrons and protons must be equal. Choice C is incorrect as it compares electrons to neutrons, which are not directly related in determining an atom's charge. Choice D is incorrect as the number of electrons in a neutral atom is not dependent on the atom's temperature but rather on the atom's balance of positive and negative charges.

Correct Answer: B

Rationale: Evaporation is the correct term for the process of converting a liquid into a gas at a temperature below its boiling point. During evaporation, molecules of the liquid gain enough energy to escape into the gas phase, primarily occurring at the liquid's surface. Vaporization is a broader term that encompasses the conversion of a substance from a liquid or solid state to a gas, not specifically at temperatures below the boiling point. Condensation is the reverse process of evaporation, involving the conversion of a gas into a liquid. Sublimation, on the other hand, refers to the direct transition of a substance from the solid phase to the gas phase without passing through the liquid phase.

Correct Answer: B

Rationale: Kidney failure is the term used to describe the inability of the kidneys to effectively filter waste products from the blood. Dehydration refers to insufficient fluid intake and not the kidney's filtering function. Incontinence is the loss of bladder control, not related to kidney filtration. Nephritis is the inflammation of the kidneys, not specifically related to the kidneys' inability to filter waste products.