Science TEAS Practice Test

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.

Correct Answer: C

Rationale: The correct answer is C: Small intestine. This is because the small intestine is where the majority of nutrient absorption occurs in the digestive system. The small intestine is lined with villi and microvilli, which greatly increase its surface area for absorption. Digestive enzymes and bile are also released in the small intestine to further break down nutrients for absorption. The stomach mainly breaks down food, the large intestine primarily absorbs water and electrolytes, and the mouth initiates digestion through chewing and mixing food with saliva.

Correct Answer: C

Rationale: The correct answer is C: The pancreas. The pancreas functions as both an endocrine and exocrine gland. It secretes digestive enzymes (exocrine function) into the small intestine and produces hormones such as insulin and glucagon (endocrine function). This dual role allows the pancreas to regulate both digestion and blood sugar levels. Incorrect Answers: A: The kidney - Functions mainly in filtration and regulation of fluid balance, not as an endocrine/exocrine gland. B: The spleen - Primarily involved in immune function and blood filtration, not as an endocrine/exocrine gland. D: The stomach - Secretes digestive enzymes, but does not have a significant endocrine function like the pancreas.

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.