A student conducts an experiment where they dissolve 1 g each of several substances in 50 mL of water. They have 12 identical plastic cups of water and places 1 g of salt into three of the cups, 1 of sugar into three of the cups, and 1 g of baking soda into three of the cups. The three remaining cups contain only water. All the cups are put in a freezer and the temperature of the solution in each cup is recorded every 15 minutes for 4 hours.

Which of the following questions is the student most likely investigating?

The experiment involves dissolving different substances in water and observing how these solutions cool. The primary variable being tested is how the type of solute (salt, sugar, baking soda) affects the cooling rate, rather than solubility or volume effects.

The correct answer is choice B. This is the plate that represents the highest number of bacteria. The bacteria that grow on this plate are the most resistant to the antibiotic because they can survive in a high concentration of the substance. In the other plates, the antibiotic inhibits the growth of the bacteria to a greater or lesser extent, depending on their sensitivity.

The correct answer is C. Psoriasis is a chronic autoimmune skin condition characterized by the rapid buildup of skin cells, and it is considered a noninfectious disease. Chikungunya, dengue, and brucellosis are infectious diseases caused by specific pathogens.

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 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 C. Biological macromolecules are large, complex molecules essential for life. Nucleic acids, such as DNA and RNA, are examples of biological macromolecules. They are composed of nucleotides and play a crucial role in genetic information storage and transfer.

Nucleic acid, is also an example of a biological macromolecule. Nucleic acids are large molecules made up of nucleotides, which consist of a nitrogenous base, a sugar molecule, and a phosphate group. DNA and RNA are examples of nucleic acids, and they play crucial roles in storing and transmitting genetic information within cells. Therefore, both Protein) and Nucleic acidare correct examples of biological macromolecules.

Phosphates are found in both DNA and cell membranes. In DNA, they form part of the backbone structure, linking the nucleotides together. In cell membranes, phosphates are a component of phospholipids, which are critical to the membrane's structure and function.

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. Emphysema is a disease that primarily affects the alveoli, which are tiny air sacs in the lungs responsible for gas exchange. The destruction of alveoli walls in emphysema reduces the surface area available for oxygen and carbon dioxide exchange.

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.