Practice TEAS Science Test

Correct Answer: B

Rationale: The correct answer is B: Protein. Proteins are macromolecules composed of amino acids, which always contain nitrogen in their structure. Amino acids have an amine group (-NH2), which is where the nitrogen is found. Fatty acids (choice A) do not contain nitrogen in their structure. Lipids (choice C) and carbohydrates (choice D) also do not contain nitrogen in their basic structure. Therefore, protein is the only macromolecule among the choices that will always contain nitrogen.

Correct Answer: B

Rationale: The correct answer is B: Depolarization of the SA node. The P-wave in an ECG represents atrial depolarization, which is initiated by the SA node. This electrical signal spreads through the atria causing them to contract. Choice A is incorrect because the P-wave corresponds to atrial depolarization, not repolarization. Choice C is incorrect as the QRS complex represents ventricular depolarization. Choice D is incorrect as the T-wave represents ventricular repolarization. Therefore, the SA node depolarization is accurately represented by the P-wave in an ECG.

Correct Answer: B

Rationale: The correct answer is B: To filter waste from the blood. The lymphatic system includes lymph nodes and vessels that help filter out waste, toxins, and pathogens from the blood. Lymphocytes in the lymph nodes also play a key role in immune responses. The other choices (A, C, D) are incorrect because the lymphatic system is not responsible for transporting oxygen (A), producing red blood cells (C), or regulating body temperature (D).

Correct Answer: D

Rationale: The correct answer is D: Epiglottis. The epiglottis is a flap of tissue that covers the opening of the windpipe (trachea) during swallowing to prevent food from entering it. Step-by-step rationale: 1. During swallowing, the epiglottis moves down to cover the trachea. 2. This action directs food to the esophagus (B), a muscular tube that carries food to the stomach. 3. The pharynx (A) is a common passageway for both food and air but does not prevent food from entering the windpipe. 4. The larynx (C) is involved in sound production but does not prevent food from entering the windpipe. In summary, the epiglottis is the correct structure as it specifically functions to protect the windpipe during swallowing, while the other choices do not have this specific function.

Correct Answer: D

Rationale: The correct answer is D: Recessive Inheritance. Mendelian inheritance follows the principles proposed by Gregor Mendel, where traits are determined by pairs of genes, with one being dominant and the other recessive. In recessive inheritance, an individual must inherit two copies of the recessive allele to exhibit the trait. This type of inheritance follows Mendel's laws of segregation and independent assortment. In contrast, incomplete dominance (A) shows blending of traits, polygenic alleles (B) involve multiple genes contributing to a single trait, and combination inheritance (C) is not a recognized term in Mendelian genetics.