TEAS 7 practice test science

Correct Answer: B

Rationale: When an atom loses an electron, it gains a positive charge and becomes an ion. This occurs because the number of protons in the atom exceeds the number of electrons, leading to a positive charge. Therefore, the atom undergoes a transformation into an ion by losing an electron. Choice A is incorrect because losing an electron does not result in the formation of a molecule, as molecules are made up of bonded atoms. Choice C is incorrect because losing an electron does not change the fundamental identity of the atom; it only changes its charge. Choice D is incorrect because losing an electron causes the atom to become positively charged, altering its neutrality.

Correct Answer: C

Rationale: The angle of reflection is determined by the angle of incidence according to the law of reflection, which states that the angle of incidence is equal to the angle of reflection. When light reflects off a surface, the angle at which it strikes the surface (angle of incidence) is the key factor in determining the angle at which it reflects (angle of reflection). The material of the surface, the wavelength of the light, and the intensity of the light do not directly influence the angle of reflection in this context. Therefore, the correct answer is the angle of incidence (Choice C). The material of the surface (Choice A) does affect other properties like reflectivity but does not directly determine the angle of reflection. The wavelength of the light (Choice B) determines its color or frequency but not the angle of reflection. The intensity of the light (Choice D) is related to the brightness of the light but does not dictate the angle at which light reflects from a surface.

Correct Answer: B

Rationale: The most common location for an ectopic pregnancy is the fallopian tube. This occurs when the fertilized egg implants and grows outside the uterus, typically in the fallopian tube. Ectopic pregnancies in other locations such as the ovary, cervix, or vagina are much rarer. The fallopian tube is the correct answer because it is the site where the fertilized egg may get stuck during its journey to the uterus, leading to implantation and growth outside the uterus. The ovary is not a common site for ectopic pregnancy, and implantation there can be life-threatening due to the risk of severe bleeding. The cervix and vagina are not typical sites for implantation of a fertilized egg, making them less likely locations for an ectopic pregnancy.

Correct Answer: B

Rationale: When a person throws a ball horizontally, the initial force that propels the ball forward is the force of throwing (A). However, the force that changes the direction of the ball's motion is the gravitational force (B). Gravitational force acts vertically downward, causing the ball to follow a curved path. Air resistance (C) and normal force from the ground (D) do not directly change the direction of the ball's motion in this scenario.

Correct Answer: D

Rationale: Fluorine-18 is the radioactive isotope commonly used in medical imaging techniques such as PET scans. It is frequently used in the form of fluorodeoxyglucose (FDG) to locate areas of heightened metabolic activity in the body, such as in cancer cells. Uranium-235 and Plutonium-239 are not typically employed in medical imaging, and Potassium-40, while a naturally occurring radioactive isotope found in the human body, is not commonly used in medical imaging techniques.