ATI TEAS 7
Mometrix TEAS 7 science practice test
1. The Hardy-Weinberg equilibrium describes a population that is:
- A. Undergoing rapid evolution due to strong directional selection.
- B. Not evolving and at genetic equilibrium with stable allele frequencies.
- C. Experiencing a founder effect leading to a reduction in genetic diversity.
- D. Dominated by a single homozygous genotype that eliminates all variation.
Correct answer: B
Rationale: The Hardy-Weinberg equilibrium describes a theoretical population in which allele frequencies remain constant from generation to generation, indicating that the population is not evolving. This equilibrium occurs under specific conditions: no mutation, no gene flow, random mating, a large population size, and no natural selection. In this scenario, all genotypes are in proportion to the allele frequencies, and genetic diversity is maintained. Options A, C, and D do not accurately describe a population in Hardy-Weinberg equilibrium. Option A suggests rapid evolution due to strong directional selection, which would disrupt the equilibrium. Option C mentions a founder effect, which can reduce genetic diversity but is not a characteristic of a population in Hardy-Weinberg equilibrium. Option D describes a population dominated by a single homozygous genotype, which also does not align with the genetic diversity seen in a population at Hardy-Weinberg equilibrium.
2. In the 18th century, women were more likely to die in childbirth compared to the 21st century. What is a possible explanation for why women are less likely to die in childbirth in the present age?
- A. Doctors are better equipped to perform cesarean sections.
- B. Doctors have more tools to monitor mothers during childbirth, enabling earlier detection of complications.
- C. Doctors practice good hand hygiene to prevent the transfer of germs and infections.
- D. All of the statements above provide reasonable explanations for the decrease in mortality during childbirth.
Correct answer: D
Rationale: All options are valid explanations for the decrease in maternal mortality during childbirth in modern times. Improved medical knowledge and technology have enabled doctors to perform cesarean sections more effectively, monitor mothers more closely for early detection of complications, and maintain better hygiene practices to reduce the risk of infections. Therefore, all the given statements collectively contribute to the reduction in maternal mortality rates in the 21st century.
3. During a healthy heartbeat, the P wave on an ECG represents
- A. The repolarization of the ventricles.
- B. The electrical conduction through the AV node.
- C. The contraction phase of the ventricles (systole).
- D. The depolarization of the atria.
Correct answer: D
Rationale: The P wave on an ECG represents the depolarization of the atria. This electrical activity initiates the contraction of the atria, allowing blood to be pumped into the ventricles. The P wave is the first positive deflection seen on the ECG and signifies the beginning of atrial depolarization, which is a critical step in the cardiac cycle. Choices A, B, and C are incorrect. Option A (The repolarization of the ventricles) is represented by the T wave on the ECG. Option B (The electrical conduction through the AV node) is not represented by the P wave but rather by the PR interval on the ECG. Option C (The contraction phase of the ventricles (systole)) is more related to the QRS complex on the ECG, which represents ventricular depolarization and contraction.
4. What is the main purpose of biological classification?
- A. To create a rigid and unchanging system for labeling organisms
- B. To understand the diversity and interconnectedness of life
- C. To simplify nature into neat and tidy categories
- D. To assign organisms to specific ecological niches
Correct answer: B
Rationale: Biological classification, also known as taxonomy, is the science of categorizing and organizing living organisms based on shared characteristics. The main purpose of biological classification is not to create a rigid and unchanging system (option A) or to simplify nature into neat and tidy categories (option C). Instead, it aims to help us understand the diversity of life on Earth and how different organisms are related to each other. By classifying organisms into groups based on their evolutionary relationships, we can gain insights into the interconnectedness of life and better appreciate the complexity and beauty of the natural world. Assigning organisms to specific ecological niches (option D) is more related to ecological studies rather than biological classification.
5. Osteoporosis is a condition that leads to weakened bones and an increased risk of fractures. Which hormone plays a key role in bone health and is often affected in osteoporosis?
- A. Estrogen
- B. Testosterone
- C. Thyroid hormone
- D. Insulin
Correct answer: A
Rationale: Estrogen plays a crucial role in maintaining bone health by inhibiting bone resorption and promoting bone formation. In postmenopausal women, estrogen levels decrease, leading to an increased risk of osteoporosis due to accelerated bone loss. This hormonal imbalance contributes to weakened bones and an increased risk of fractures in individuals with osteoporosis. Testosterone and thyroid hormone do play roles in bone health, but estrogen has a more significant impact. Testosterone is more commonly associated with muscle mass and strength, while thyroid hormone regulates metabolism. Insulin is not directly involved in bone health and is not typically affected in osteoporosis.
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