a solution is formed when

ATI TEAS 7

Mometrix TEAS 7 science practice test

1. When is a solution formed?

A. One substance dissolves in another
B. Two or more substances react chemically
C. A solid changes to a liquid
D. None of the above

Correct answer: A

Rationale: A solution is formed when one substance dissolves in another. This process creates a homogeneous mixture where the solute is dispersed in the solvent, resulting in a uniform composition throughout the mixture. Choice B is incorrect because chemical reactions involve the transformation of substances into new compounds, not the formation of solutions. Choice C is incorrect as it describes a physical change from a solid to a liquid, not the formation of a solution. Choice D is incorrect as one substance dissolving in another is the defining characteristic of a solution.

2. What is the term for the process of a gas changing directly into a solid?

A. Condensation
B. Deposition
C. Sublimation
D. Evaporation

Correct answer: B

Rationale: The correct term for the process of a gas changing directly into a solid is deposition. During deposition, gas particles lose energy and transition directly into the solid state without passing through the liquid phase. Sublimation, on the other hand, is the process in which a solid changes directly into a gas without going through the liquid phase. Condensation is the process where gas changes into a liquid state. Evaporation, on the contrary, is the conversion of a liquid to a gas. Therefore, the correct answer is B, deposition.

3. The Hardy-Weinberg equilibrium describes a population that is:

A. Undergoing rapid evolution due to strong directional selection.
B. Not evolving and at genetic equilibrium with stable allele frequencies.
C. Experiencing a founder effect leading to a reduction in genetic diversity.
D. Dominated by a single homozygous genotype that eliminates all variation.

Correct answer: B

Rationale: The Hardy-Weinberg equilibrium describes a theoretical population in which allele frequencies remain constant from generation to generation, indicating that the population is not evolving. This equilibrium occurs under specific conditions: no mutation, no gene flow, random mating, a large population size, and no natural selection. In this scenario, all genotypes are in proportion to the allele frequencies, and genetic diversity is maintained. Options A, C, and D do not accurately describe a population in Hardy-Weinberg equilibrium. Option A suggests rapid evolution due to strong directional selection, which would disrupt the equilibrium. Option C mentions a founder effect, which can reduce genetic diversity but is not a characteristic of a population in Hardy-Weinberg equilibrium. Option D describes a population dominated by a single homozygous genotype, which also does not align with the genetic diversity seen in a population at Hardy-Weinberg equilibrium.

4. How does lymph move through the lymphatic vessels?

A. By the pumping action of the heart
B. Due to muscle contractions and breathing movements
C. Through one-way valves within the vessels
D. All of the above

Correct answer: C

Rationale: Lymph moves through the lymphatic vessels due to the presence of one-way valves within the vessels. These valves prevent the backflow of lymph and help propel the fluid forward as muscles contract and relax or due to breathing movements. Unlike blood circulation, the lymphatic system does not rely on the pumping action of the heart to move lymph. Choice A is incorrect because lymphatic circulation does not depend on the pumping action of the heart. Choice B is partly correct as muscle contractions and breathing movements do assist in propelling lymph, but the primary mechanism is the presence of one-way valves within the vessels, making choice C the most accurate answer. Choice D is incorrect as not all options listed contribute to how lymph moves through the lymphatic vessels.

5. Which of the following organelles is responsible for producing ATP in the cell?

A. Golgi apparatus
B. Mitochondria
C. Nucleus
D. Ribosome

Correct answer: B

Rationale: Mitochondria are the powerhouse of the cell and are responsible for producing ATP through cellular respiration. ATP, or adenosine triphosphate, is the energy currency of the cell that is essential for various cellular processes. The Golgi apparatus is involved in modifying, sorting, and packaging proteins for secretion. The nucleus is responsible for housing the cell's genetic material and controlling cell activities. Ribosomes are involved in protein synthesis. However, the actual production of ATP occurs in the mitochondria through processes like the citric acid cycle and oxidative phosphorylation.