TEAS 7 science practice

Correct Answer: B

Rationale: A) Founder effect: This occurs when a small group of individuals establishes a new population, leading to a loss of genetic variation compared to the original population. It does not necessarily result in a gradual loss of genetic variation in an existing population. B) Bottleneck effect: This process occurs when a population is drastically reduced in size, leading to a significant loss of genetic variation due to the limited number of individuals contributing to the gene pool. The reduced genetic diversity can have long-term effects on the population's ability to adapt to environmental changes. C) Gene flow: This refers to the movement of genes between populations, which can introduce new genetic variation and prevent populations from diverging. Gene flow does not lead to a gradual loss of genetic variation within a population. D) Speciation: This is the process by which new species evolve from existing species, often involving the accumulation of genetic differences that l

Correct Answer: A

Rationale: The speed of a wave in a given medium is determined by the product of its frequency and wavelength. This relationship is described by the formula: Speed = Frequency Wavelength. When a wave travels through a medium, the speed at which it propagates is directly proportional to both its frequency and wavelength. Therefore, to calculate the speed of the wave, you multiply the frequency of the wave by its wavelength. Choices B, C, and D are incorrect because speed is not determined by division, addition, or subtraction of frequency and wavelength; instead, it is determined by their multiplication in the given medium.

Correct Answer: C

Rationale: Rusting iron is an example of a chemical change because it involves a chemical reaction where iron reacts with oxygen in the presence of water to form iron oxide (rust). This reaction results in a change in the chemical composition of the iron, unlike dissolving sugar in water, boiling water, or crushing ice, which are physical changes. Dissolving sugar in water is a physical change as sugar molecules remain unchanged but disperse in water. Boiling water is also a physical change as water changes its state from liquid to gas due to heat. Crushing ice is a physical change as the solid ice changes its physical form without altering its chemical composition.

Correct Answer: A

Rationale: The medulla oblongata is the correct answer. It is responsible for controlling vital functions such as heart rate, blood pressure, and breathing. This part of the brainstem contains centers that regulate these essential autonomic functions to maintain homeostasis in the body. The pons and midbrain are also parts of the brainstem, but they are not primarily responsible for controlling these vital functions. The cerebellum, on the other hand, is involved in coordination and balance, not in regulating vital functions like heart rate, blood pressure, and breathing.

Correct Answer: B

Rationale: The Law of Segregation, proposed by Gregor Mendel, states that alleles for a gene segregate during gamete formation. This means that each parent passes on only one allele for each gene to their offspring. This law explains how genetic diversity is maintained and how different combinations of alleles are generated in offspring. The Law of Independent Assortment (option A) is not the correct answer as it states that alleles of different genes assort independently of each other during gamete formation, not specifically alleles of a single gene. The Law of Dominance (option C) is incorrect as it pertains to the expression of alleles rather than their segregation during gamete formation. The Law of Probability (option D) is also incorrect as it is a general concept describing the likelihood of events, not specifically related to alleles segregating during gamete formation.