Science TEAS Practice Test

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: B

Rationale: The correct answer is B, "Most of them are gases at room temperature." Metals are typically solid at room temperature, not gases. This is because metals have high melting points due to their metallic bonding structure. Choice A is true as most metals are good conductors of heat due to the free movement of electrons. Choice C is also true, as metals are ductile and can be drawn into wires. Choice D is incorrect, as metals do not make up the majority of elements on the periodic table. Nonmetals, metalloids, and noble gases also exist.

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: Covalent. In DNA, sugar and phosphate molecules are joined together by covalent bonds. Covalent bonds involve sharing of electrons between atoms, providing a strong and stable connection. This type of bond is essential for the structural integrity of the DNA molecule. A: Hydrogen bonds are important in DNA structure, but they connect the nitrogenous bases, not sugar and phosphate. B: Ionic bonds involve the transfer of electrons between atoms, not sharing, and are not typically involved in connecting sugar and phosphate in DNA. D: "Overt" is not a recognized type of chemical bond; it is an incorrect distractor.

Correct Answer: D

Rationale: The correct answer is D because all the statements provide reasonable explanations for the decrease in mortality during childbirth in the 21st century. A: Cesarean sections can be life-saving in cases of complications like prolonged labor or fetal distress. B: Monitoring tools help detect issues early, allowing for timely interventions and prevention of complications. C: Good hand hygiene reduces the risk of infections that could lead to maternal mortality. Therefore, by combining the advancements in cesarean sections, monitoring tools, and infection prevention practices, modern healthcare has significantly reduced maternal mortality rates compared to the 18th century.