Science TEAS Practice Test

Correct Answer: B

Rationale: The correct answer is B. If an organism is AB, it means they have alleles A and B. In gametes, each gamete carries only one allele. Therefore, gametes with AA are not possible as they lack the B allele. Gametes with AB are possible since they can carry either A or B allele. Gametes with BB are not possible as they lack the A allele. Gametes with AB are possible as they can carry either A or B allele.

Correct Answer: B

Rationale: The correct answer is B: Thymine. Thymine is a nucleobase that exists in DNA, not RNA. RNA contains Uracil instead of Thymine. This is due to a different chemical structure in RNA which lacks the methyl group present in Thymine. Uracil pairs with Adenine in RNA, while Thymine pairs with Adenine in DNA. Choices A, C, and D (Uracil, Cytosine, Guanine) are all nucleobases found in RNA, making them incorrect answers.

Correct Answer: D

Rationale: The correct answer is D because T cells play a crucial role in the immune response by recognizing and attacking infected cells or pathogens. They are a type of white blood cell, making choice B valid. Choice C is accurate as T cells mature in the thymus during their development. Choice A is incorrect because T cells are present in all individuals, not just those with leukemia.

Correct Answer: A

Rationale: The correct answer is A: Condensation is the process of changing from a gas to a liquid. This is because condensation occurs when a gas loses heat energy and transitions into a liquid state. The gas molecules slow down and come closer together, forming liquid droplets. Explanation: 1. In condensation, gas molecules lose energy and move closer together. 2. This causes the gas to transition into a liquid state. 3. The process of condensation is commonly observed in everyday situations like when water vapor in the air cools and forms dew on a cold surface. Summary: B: Changing from a liquid to a gas is called evaporation, not condensation. C: Changing from a solid to a liquid is called melting, not condensation. D: Changing from a solid to a gas is called sublimation, not condensation.

Correct Answer: B

Rationale: The correct answer is B: A gene. A gene is the smallest unit that can encode for a trait because it is a specific sequence of nucleotides in the DNA that provides instructions for a particular trait or function. Genes determine our physical characteristics and traits. A codon (choice A) is a sequence of three nucleotides that code for a specific amino acid in protein synthesis, not a complete trait. A nucleotide (choice C) is the basic building block of DNA, but it is not capable of encoding for a trait on its own. A chromosome (choice D) is made up of DNA and contains multiple genes, so it is not the smallest unit that can encode for a trait.