TEAS 7 science practice questions

Correct Answer: B

Rationale: The balanced chemical equation for the combustion of methane is: CH4 + 2O2 -> CO2 + 2H2O. This equation shows that 1 mole of methane produces 2 moles of water. Therefore, when 0.5 moles of methane react, they will produce 1 mole of water. The ratio of water to methane is 2:1, meaning that for every mole of methane that reacts, it produces 2 moles of water. Since only 0.5 moles of methane are reacting, the amount of water produced will be half of what would be produced if 1 mole of methane reacted, resulting in 1 mole of water being produced. Choice A is incorrect because it does not consider the stoichiometry of the reaction. Choices C and D are incorrect as they do not align with the balanced chemical equation and the stoichiometric ratios involved in the reaction.

Correct Answer: C

Rationale: The alveoli are tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide occurs. Oxygen from the air diffuses into the bloodstream through the alveoli, while carbon dioxide from the bloodstream diffuses into the alveoli to be exhaled. The trachea, bronchi, and bronchioles are essential parts of the airway system responsible for transporting air to and from the lungs but do not directly participate in the gas exchange process. Therefore, option C, the alveoli, is the correct answer for the structure responsible for the exchange of oxygen and carbon dioxide between the lungs and the bloodstream.

Correct Answer: B

Rationale: Energy is the capacity to do work, while power is the rate at which work is done or energy is transferred. Power is the amount of energy transferred or converted per unit time. Therefore, energy is related to power as the rate at which work is done. Choice A is incorrect because power and energy are not the same; they are related concepts but represent different aspects. Choice C is incorrect because power does not refer to stored energy but rather the rate of energy transfer. Choice D is incorrect because energy is not the rate at which power is transferred, but the capacity to do work or cause change.

Correct Answer: B

Rationale: Bone is composed of connective tissue. Connective tissues are characterized by having cells scattered within an extracellular matrix. In the case of bone, the extracellular matrix is mineralized, giving bone its hardness and strength. Choice A, epithelial tissue, is not correct as bone is not primarily composed of epithelial cells. Choice C, hard connective tissue, is not a recognized category of tissue in the scientific classification; bone is classified under connective tissue. Choice D, muscle tissue, is incorrect as bone and muscle tissues are distinct types of tissues with different structures and functions.

Correct Answer: A

Rationale: Calcitonin is the hormone produced by the thyroid gland that regulates calcium levels in the blood. It enhances calcium absorption in the intestines and reduces calcium loss in the kidneys. Parathyroid hormone (PTH) operates oppositely to calcitonin by increasing calcium levels in the blood. Thyroxine is a thyroid gland hormone that primarily regulates metabolism, not calcium levels. Insulin, produced by the pancreas, is responsible for controlling blood sugar levels, not calcium levels. Therefore, the correct answer is Calcitonin as it specifically targets calcium regulation in the body.