Science TEAS Practice Test

Correct Answer: D

Rationale: Step-by-step rationale: 1. Meiosis involves two rounds of cell division. 2. In meiosis I, homologous chromosomes separate, resulting in haploid daughter cells with half the number of chromosomes. 3. In meiosis II, sister chromatids separate, resulting in four haploid daughter cells. 4. Since humans have 46 chromosomes in their somatic cells, each resulting cell after meiosis will contain 23 chromosomes. Summary: A: 96 is incorrect as it is a doubled diploid number. B: 54 is incorrect as it is not the correct halving of the diploid human chromosome number. C: 46 is incorrect as it represents the original number of chromosomes in a human somatic cell, not the resulting number after meiosis.

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.

Correct Answer: C

Rationale: The correct answer is C: Epidermis. The epidermis is the outermost layer of the skin and is avascular, meaning it does not contain blood vessels. This is important for maintaining its protective function and preventing blood loss in case of injury. The hypodermis (A) contains blood vessels that supply the skin with nutrients and regulate temperature. The dermis (B) is rich in blood vessels, providing nourishment to the skin and regulating temperature. Option D (Hyperdermis) is not a recognized layer of the skin, making it an incorrect choice.

Correct Answer: A

Rationale: The correct answer is A: Phenotype. Phenotype refers to the physical and visible expression of a genetic trait. It includes observable characteristics like eye color, height, and hair texture. This is different from genotype, which represents the genetic makeup of an organism. Allele refers to different forms of a gene, and gamete is a reproductive cell. Thus, in this context, phenotype best describes the physical manifestation of a genetic trait, making it the correct answer.

Correct Answer: C

Rationale: The correct answer is C: Circulatory system. This system, composed of the heart, blood vessels, and blood, is responsible for transporting nutrients, gases, and wastes throughout the body. The heart pumps blood carrying oxygen and nutrients to cells and removes waste products. The blood vessels distribute these substances to tissues and organs. The respiratory system (A) is responsible for gas exchange but not for transporting nutrients and wastes. The digestive system (B) processes food and absorbs nutrients but does not transport gases. The nervous system (D) coordinates body functions and transmits signals but does not transport nutrients, gases, or wastes.