Practice Science TEAS Test

Correct Answer: C

Rationale: The correct answer is C because DNA is indeed read 5' to 3', not 3' to 5'. This directionality is essential for DNA replication and protein synthesis. Choice A is correct as DNA contains A, T, C, G nucleotides and is read 5' to 3'. Choice B is correct as DNA carries genetic information and forms chromosomes with proteins. Choice D is correct as DNA is double-stranded with hydrogen bonds holding the two strands together.

Correct Answer: B

Rationale: The correct answer is B: Semicircular canals. These structures are filled with fluid and lined with tiny hair cells that detect movement and changes in head position, helping maintain balance. The other choices are incorrect because: A: Cochlea is responsible for hearing, not balance. C: Eardrum helps transmit sound vibrations, but not related to balance. D: Auditory nerve carries signals from the ear to the brain for hearing, not balance.

Correct Answer: B

Rationale: The correct answer is B: To contract and expand the lungs. The diaphragm is a dome-shaped muscle that plays a crucial role in respiration by contracting and relaxing to create changes in lung volume, allowing air to flow in and out of the lungs. When the diaphragm contracts, it flattens, increasing the space in the chest cavity and causing inhalation. When it relaxes, it returns to its dome shape, decreasing the space in the chest cavity and causing exhalation. Incorrect choices: A: To regulate air pressure in the lungs - While the diaphragm indirectly affects air pressure by creating changes in lung volume, its primary role is in creating the necessary space for inhalation and exhalation. C: To store oxygen - The diaphragm is a muscle and does not store oxygen. Oxygen is primarily stored in the blood and tissues. D: To break down carbon dioxide - The diaphragm is not involved in breaking down carbon dioxide. Carbon dioxide is

Correct Answer: A

Rationale: The correct answer is A: Ionic bond. In KCl, potassium (K) is a metal and chlorine (Cl) is a nonmetal. Ionic bonds form between a metal and a nonmetal through the transfer of electrons. In KCl, potassium donates an electron to chlorine, resulting in the formation of K+ and Cl- ions, which are held together by electrostatic forces. Covalent bonds (choice B) involve the sharing of electrons between two nonmetals, which is not the case in KCl. Hydrogen bonds (choice C) occur between molecules with hydrogen and electronegative atoms like oxygen or nitrogen, not between ionic compounds. Polar covalent bonds (choice D) involve unequal sharing of electrons between nonmetals, which is not the case in KCl where there is a complete transfer of electrons.

Correct Answer: D

Rationale: The correct answer is D: Thyroid. The thyroid gland produces hormones such as thyroxine and triiodothyronine, which play a crucial role in regulating metabolism. These hormones control the body's metabolic rate, affecting processes like energy production and consumption. The thymus (A) is responsible for immune function, the pituitary gland (B) regulates various hormones but not specifically metabolism, and the pancreas (C) produces insulin and glucagon to regulate blood sugar levels, not metabolism directly. In summary, the thyroid gland is the correct choice as it specifically regulates metabolism through thyroid hormones.