Which of the following is an example of a biological macromolecule?

The correct answer is B. Facilitated diffusion is the passive movement of molecules, including water, across a membrane with the help of specific transport proteins. Water moves through specialized channels called aquaporins during facilitated diffusion.

The correct answer is C. Lysosomes are membrane-bound organelles containing enzymes that break down cellular waste, debris, and foreign materials through intracellular digestion.

The correct answer is C. The renal vein is responsible for draining oxygen-depleted blood from the kidneys. After the kidneys filter waste and excess substances from the blood, the deoxygenated blood is carried away from the kidneys by the renal vein

The correct answer is B. Atoms become cations by losing electrons. Potassium has one electron in its outermost shell, and it is more likely to lose that electron to achieve a stable, cationic state. Fluorine, helium, and oxygen are more likely to gain electrons and form anions.

The correct answer is B. Electrons are much lighter than protons and neutrons and have a negligible mass compared to them. Therefore, when calculating the atomic mass number, electrons are typically not considered.

The correct answer is B. Objects A and B have the same mass, but B falls faster because it has less air resistance. Objects C and D have different masses, but C falls faster because it has a higher mass-to-surface-area ratio, which reduces the effect of air resistance.

The correct answer is B. Uracil is a nitrogenous base found in RNA, replacing thymine which is found in DNA. Adenine, guanine, and cytosine are common to both RNA and DNA.

The correct answer is C. A spectrophotometer measures the amount of light absorbed or transmitted by a substance in a liquid. Turbidity, caused by suspended particles, can be assessed by measuring the reduction in light transmission through the sample. The other tools listed are not specifically designed for measuring turbidity.

The correct answer is A. The endocardium is the innermost layer of tissue that lines the interior surfaces of the heart, providing a smooth surface for blood flow. The myocardium is the middle muscular layer, the pericardium is the outer protective sac, and the epicardium is the outermost layer covering the heart.

The correct answer is A. This option describes a chemical reaction known as the reaction of water with sodium, producing hydrogen gas. Chemical reactions involve the breaking and forming of chemical bonds, and in this case, sodium reacts with water to produce hydrogen gas and sodium hydroxide.