TEAS 7 Science Practice Test

Correct Answer: C

Rationale: The correct answer is C because isotopes are atoms of the same element that have different numbers of neutrons. Neutrons are the subatomic particles that do not have a charge and are found in the nucleus of an atom. Different isotopes of an element have the same number of protons (which determines the element's identity) but vary in the number of neutrons, leading to differences in atomic mass. This distinction in neutron number is the defining characteristic of isotopes. Choices A, B, and D are incorrect: A: Isotopes do not have different ionic charges as they have the same number of protons and electrons, maintaining overall charge neutrality. B: Isotopes can be found across different groups on the periodic table, not restricted to the same group. D: Isotopes can have the same electron configurations since electrons are primarily determined by the number of protons in the nucleus, which remains constant for isotopes of the same element.

Correct Answer: D

Rationale: The correct answer is D: conducting and respiratory. The conducting zone consists of structures that conduct air to the respiratory zone where gas exchange occurs. The respiratory zone includes the alveoli where oxygen is absorbed and carbon dioxide is released. Choices A, B, and C do not accurately represent the major zones of the respiratory system. The left and right bronchi are part of the conducting zone, not major zones. The nose and mouth are entry points but not major zones. The larynx and pharynx are part of the upper respiratory tract, not major zones.

Correct Answer: D

Rationale: The correct answer is D: neuromuscular junction. This is where nerve impulses travel to release neurotransmitters, such as acetylcholine, to stimulate muscle contraction. The sarcomere is the basic unit of muscle contraction, not the location of neurotransmitter release. Tendons connect muscles to bones and do not involve neurotransmitter release. The myelin sheath is a protective layer around nerves and is not directly involved in neurotransmitter release at the neuromuscular junction.

Correct Answer: A

Rationale: The correct answer is A. Progesterone is not responsible for the expression of secondary sexual characteristics, such as enlarged breasts. Progesterone's main functions in the female reproductive system are to regulate and prepare the endometrial lining of the uterus for potential pregnancy, inhibit contractions of the uterus as the ovum is released, and stimulate milk production in the breasts. Enlarged breasts are primarily influenced by estrogen, another hormone in the female reproductive system. Thus, A is the correct answer as it does not align with the known functions of progesterone.

Correct Answer: B

Rationale: The correct answer is B: A dominant allele will always be expressed. This is because dominant alleles mask the expression of recessive alleles in heterozygous individuals. This means that if an individual carries at least one dominant allele for a particular trait, that dominant allele will be expressed phenotypically. In contrast, recessive alleles are only expressed when an individual is homozygous for that allele. Now, let's analyze the other choices: A: All genes adhere to Mendel's law of dominance - This is incorrect as not all genes follow Mendel's law of dominance, especially in cases of incomplete dominance or codominance. C: When two dominant alleles are present, the resulting phenotype will express both traits - This is incorrect as dominance determines which allele is expressed, so only the dominant trait will be expressed in this case. D: There are three or more alleles possible for all genes - This is incorrect as some genes may have multiple alleles, but not all genes have three