TEAS 7 science practice

Correct Answer: A

Rationale: A saturated hydrocarbon chain contains only single bonds between carbon atoms, making it 'saturated' with hydrogen atoms. Therefore, the correct answer is choice A, 'Saturated.' Choice B, 'Unsaturated,' is incorrect because it refers to hydrocarbon chains with double or triple bonds. Choice C, 'Aromatic,' is not the correct term for a hydrocarbon chain without double or triple bonds; it describes a specific type of cyclic and conjugated hydrocarbon structure. Choice D, 'Alkene,' is also incorrect as it specifically indicates a hydrocarbon chain with at least one double bond between carbon atoms.

Correct Answer: B

Rationale: Elasticity is the correct term that describes the ability of a muscle to return to its original length and shape after being stretched or contracted. Contractility refers to the ability of a muscle to contract or shorten. Extensibility is the ability of a muscle to be stretched. Excitability is the ability of a muscle to receive and respond to stimuli. Therefore, the correct answer is 'Elasticity' as it specifically relates to the muscle's ability to regain its original form.

Correct Answer: D

Rationale: When a car is traveling at a constant speed on a straight road, it indicates that the forces acting on the car are balanced. In this scenario, there is no acceleration or deceleration, meaning the net force on the car is zero. If there was a net force present, it would cause the car to either accelerate or decelerate. Choices A, B, and C are incorrect because in a situation where a car is moving at a constant speed, the forces are balanced, and there is no unbalanced force acting in any specific direction.

Correct Answer: B

Rationale: Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. Since the atomic mass of an element is the weighted average of the masses of its isotopes, the presence of isotopes causes the atomic mass of an element to vary slightly. This variation occurs because different isotopes have different masses due to their varying numbers of neutrons. The atomic mass is affected by the abundance of each isotope, leading to a slight fluctuation in the overall atomic mass of the element. Choice A is incorrect because isotopes do influence the atomic mass. Choice C is incorrect because isotopes have different masses, affecting the overall atomic mass. Choice D is incorrect as isotopes typically do not cause a significant variation in atomic mass, but rather a slight fluctuation.

Correct Answer: B

Rationale: Inertia is the resistance of an object to changes in its state of motion. The greater the mass of an object, the greater its inertia because it requires more force to change its state of motion. This concept aligns with Newton's first law of motion, which states that an object at rest will remain at rest, and an object in motion will continue in motion with the same speed and direction unless acted upon by an external force. Therefore, higher mass increases inertia, making it more difficult to alter the object's state of motion. Choice A is incorrect as mass does impact inertia. Choice C is incorrect as higher mass actually increases inertia, not decreases it. Choice D is incorrect as while mass does affect gravitational force, it also directly impacts inertia.