Science TEAS Practice Test

Correct Answer: A

Rationale: The correct answer is A: The human body has evolved to become more resilient to its environment. This statement is not likely to have contributed to the longer life expectancy in the 21st century. Evolution occurs over long periods of time, not within a span of a few hundred years. Advances in medical technology and treatments (B), higher standards of basic cleanliness (C), and the creation of vaccines (D) have all played significant roles in increasing life expectancy by preventing and treating diseases, improving overall health, and reducing mortality rates. These factors are directly linked to improvements in healthcare and sanitation practices, which have had a tangible impact on life expectancy.

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: D

Rationale: The correct answer is D because the immune system is responsible for protecting the body from infections by identifying and eliminating harmful pathogens. It helps the body recognize and respond to foreign invaders such as bacteria and viruses. The hypothalamus (Choice A) is not directly involved in immune system function. While the immune system can help remove toxins, its primary role is to combat infections, not filter toxins from the blood (Choice B). Although infections can sometimes trigger the production of more white blood cells, the immune system's primary function is not to stimulate blood cell production (Choice C).

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: B

Rationale: The correct answer is B: Endocrine system. The adrenal glands are a crucial part of the endocrine system as they produce hormones such as cortisol and adrenaline. These hormones regulate various bodily functions like metabolism, stress response, and blood pressure. The immune system (A) is responsible for defending the body against pathogens, not producing hormones. The lymphatic system (C) is involved in immunity and fluid balance, but not hormone production. The respiratory system (D) is responsible for gas exchange in the body, not hormone regulation. Therefore, the adrenal glands being part of the endocrine system is the most accurate choice.