TEAS 7 practice test science

Correct Answer: A

Rationale: - Adaptive radiation is a process where a single ancestral species diversifies into multiple descendant species to exploit different ecological niches within a heterogeneous environment. - This diversification occurs due to the different selective pressures present in various habitats, leading to the evolution of distinct traits and adaptations in different descendant species. - Option A accurately describes the process of adaptive radiation, where the initial species undergoes rapid speciation to occupy different ecological roles and adapt to diverse environmental conditions. - Options B, C, and D do not accurately describe adaptive radiation but refer to other evolutionary processes such as convergent evolution, natural selection, and gaps in the fossil record, respectively.

Correct Answer: B

Rationale: Antagonist muscles are pairs of muscles that work in opposition to each other, producing opposing movements. When one muscle contracts, the other relaxes to allow the movement to occur smoothly. Synergists are muscles that work together to create a movement, not in opposition. Agonists are muscles primarily responsible for producing a specific movement, not opposing each other. Fixators are muscles that stabilize joints to allow other movements to take place, providing a stable base for muscle actions but do not produce opposing movements.

Correct Answer: D

Rationale: The muscular system is responsible for movement, maintaining posture, and generating heat. Regulating blood sugar levels is not a function of the muscular system. This function is primarily carried out by the endocrine system, specifically the pancreas and its production of insulin and glucagon. Choices A, B, and C are all correct functions of the muscular system as they involve the contraction and relaxation of muscles to produce movement, support the body's structure, and generate heat as a byproduct of muscle activity.

Correct Answer: C

Rationale: The cerebellum is the part of the brain that plays a crucial role in the regulation of balance, coordination, and posture. It receives information from the sensory systems, the spinal cord, and other parts of the brain to coordinate voluntary movements. While the thalamus is involved in relaying sensory and motor signals to the cerebral cortex, the cerebrum is responsible for higher brain functions such as thought and action. The hypothalamus is involved in various bodily functions including the regulation of body temperature, hunger, and thirst, but it is not primarily responsible for balance, coordination, and posture. Therefore, the correct answer is the cerebellum.

Correct Answer: D

Rationale: Autosomal dominant inheritance results in a 3:1 ratio of dominant to recessive phenotypes in the F2 generation. This inheritance pattern occurs when a single copy of the dominant allele is enough to express the dominant phenotype. A) Incomplete dominance: In incomplete dominance, the heterozygous phenotype is a blend of the two homozygous phenotypes, and it does not lead to a 3:1 ratio of dominant to recessive phenotypes in the F2 generation. B) Codominance: In codominance, both alleles are fully expressed in the heterozygous phenotype, but this pattern also does not result in a 3:1 ratio of dominant to recessive phenotypes in the F2 generation. C) Sex-linked inheritance: Sex-linked inheritance involves genes located on the sex chromosomes and does not typically lead to a 3:1 ratio of dominant to recessive phenotypes in the F2 generation.