TEAS 7 science practice questions

Correct Answer: D

Rationale: The correct answer is D, 'Boiling point elevation.' Boiling point elevation is a colligative property that describes the increase in the boiling point of a solvent when a non-volatile solute is added to it. This occurs because the presence of solute particles in the solvent lowers the vapor pressure of the solution, requiring a higher temperature to reach the same vapor pressure as the pure solvent. Choices A, B, and C are incorrect. Freezing point depression refers to the lowering of the freezing point of a solution, vapor pressure lowering is the reduction in vapor pressure due to the presence of solute particles, and osmotic pressure is the pressure required to prevent the flow of solvent molecules across a semipermeable membrane in osmosis.

Correct Answer: A

Rationale: Aldosterone is a hormone produced by the adrenal glands that plays a crucial role in maintaining electrolyte balance, specifically by regulating sodium and potassium levels in the body. Its primary function involves acting on the kidneys to increase the reabsorption of sodium and water while promoting the excretion of potassium. This process is essential for regulating blood pressure, fluid balance, and electrolyte concentrations in the body. Epinephrine is associated with the fight or flight response, cortisol is a stress hormone, and insulin is responsible for regulating blood sugar levels as produced by the pancreas. Therefore, the correct answer is Aldosterone as it directly targets electrolyte balance, particularly sodium and potassium, in the body.

Correct Answer: B

Rationale: A spasm is a repetitive, involuntary muscle contraction that can cause pain and stiffness. While cramps are a type of spasm, not all spasms are cramps. Tics are sudden, repetitive movements or sounds made involuntarily. Fibrosis refers to the formation of excess fibrous connective tissue in an organ or tissue as part of a reparative or reactive process. In this context, a spasm best fits the description provided, making it the correct answer. Cramp, although related to spasms, is more specific and not the general term being sought. Tic does not describe a muscle contraction but rather sudden movements or sounds. Fibrosis does not directly relate to muscle contractions but rather to the formation of excess fibrous tissue in organs or tissues.

Correct Answer: A

Rationale: A molecular clock is a method used to estimate the time of divergence between species by measuring the accumulation of mutations in DNA sequences. This method relies on the assumption that mutations occur at a relatively constant rate over time. If the rate of mutation were not constant, it would be challenging to accurately estimate the evolutionary divergence time between species. Therefore, option A is the most appropriate choice as it aligns with the fundamental principle underlying the molecular clock hypothesis. Option B is incorrect because the assumption that species with more morphological similarities diverged more recently does not directly relate to the concept of molecular clocks and the accumulation of mutations in DNA sequences. Option C is incorrect because mutations are not always beneficial and do not always contribute to increased fitness. Mutations can be neutral or deleterious as well, and their accumulation is what is used to estimate evolutionary di

Correct Answer: D

Rationale: The resolution of an optical instrument, such as a microscope, refers to its ability to distinguish between very close, nearly identical objects. This is crucial in microscopy to clearly visualize and differentiate fine details and structures. Resolving power plays a significant role in determining the quality and effectiveness of an optical instrument. Choices A, B, and C are incorrect because the resolution of an optical instrument does not primarily deal with different colors of light, presence or absence of light, or variations in intensity. Instead, it specifically focuses on the instrument's ability to differentiate between objects that are very close and nearly identical in nature.