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: A

Rationale: Step-by-step rationale for answer A: 1. Oxygenated blood from the lungs enters the left atrium. 2. It then passes through the mitral valve into the left ventricle. 3. Upon contraction, it is pumped into the aorta. 4. The oxygenated blood is then dispersed to tissues through a network of arteries and capillaries. Summary of why other choices are incorrect: B: Incorrect because oxygenated blood does not go to the right side of the heart. C: Incorrect because there is no direct connection between the left atrium and the right aorta. D: Incorrect because there is no septal valve and oxygenated blood is not stored in the left ventricle.

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: B

Rationale: To calculate the grams of CaCO3 needed, we first find the molar mass of CaCO3: 40.07 (Ca) + 12.01 (C) + (15.99 x 3) (O) = 100.08 g/mol. Next, use the formula: grams = moles x molar mass. Moles = 0.35 M x 0.6 L = 0.21 moles. Therefore, grams = 0.21 moles x 100.08 g/mol = 21.02 g. Hence, the correct answer is B: 19.7 g. Other choices are incorrect due to miscalculation or incorrect conversion.

Correct Answer: A

Rationale: The correct answer is A: The sinoatrial node. The SA node is known as the heart's natural pacemaker as it initiates electrical impulses that regulate the heart rate. It is located in the right atrium and generates rhythmic electrical signals that stimulate the cardiac muscle to contract. The left ventricle (B), aorta (C), and tricuspid valve (D) do not serve as electrical stimulators of the cardiac muscle. The left ventricle is a chamber that pumps oxygenated blood, the aorta is the largest artery that carries blood away from the heart, and the tricuspid valve controls blood flow between the right atrium and right ventricle.