ATI TEAS Practice Science Test

Correct Answer: A

Rationale: During Prophase I of meiosis, chiasmata structures form as homologous chromosomes exchange genetic material through crossing over. This occurs after homologous chromosomes pair up during synapsis. Chiasmata play a crucial role in genetic diversity. In contrast, Prophase II is focused on preparing the cells for division, and chiasmata formation does not occur during this phase. Metaphase I is characterized by the alignment of homologous chromosomes at the metaphase plate, while Metaphase II involves the alignment of sister chromatids. Therefore, the correct answer is A: Prophase I, as it is the specific phase where chiasmata formation takes place.

Correct Answer: D

Rationale: The correct answer is D: Oxygen. 1. Oxygen has 8 electrons in total, with 2 in the first shell and 6 in the second shell, following the 2-8-8 electron configuration rule. 2. Beryllium has 4 electrons with 2 in the first shell and 2 in the second shell. 3. Carbon has 6 electrons with 2 in the first shell and 4 in the second shell. 4. Helium has 2 electrons, filling the first shell. Therefore, Oxygen is the only element among the choices that fits the description of having 2 electrons in the first shell and 6 electrons in the second shell.

Correct Answer: A

Rationale: The correct answer is A: Forms neural circuits. Interneurons are responsible for forming connections between sensory neurons and motor neurons, creating neural circuits that allow for complex processing and coordination of signals within the central nervous system. They do not directly interact with effectors (choice B), send impulses to the CNS (choice C), or function as efferent nerve cells (choice D). Interneurons integrate and relay information within the CNS, playing a crucial role in coordinating various functions such as reflexes, sensory processing, and motor control.

Correct Answer: A

Rationale: The correct answer is A: Flagellum. Cells rely on flagella for movement because flagella are whip-like structures that enable cells to propel themselves through fluid environments. Flagella are composed of microtubules, which provide structural support and enable movement through their bending and contracting motion. Microtubules alone (B) do not facilitate movement; they serve as a scaffold within cells. Pili (C) are short, hair-like structures used for attachment rather than movement. Vesicles (D) are membrane-bound sacs involved in transportation within cells, not in cell movement. Therefore, flagellum is the most suitable structure for cellular movement.

Correct Answer: A

Rationale: The correct answer is A: Diffusion. Gas exchange in the respiratory system occurs through diffusion, where oxygen moves from the alveoli in the lungs to the blood and carbon dioxide moves from the blood to the alveoli. This process is driven by a concentration gradient, allowing for the exchange of gases between the air and blood. Exhalation (choice B) is the process of expelling air from the lungs, not the mechanism of gas exchange. Inspiration (choice C) is the process of inhaling air into the lungs, but it is not directly involved in gas exchange. Ventilation (choice D) refers to the movement of air into and out of the lungs and is necessary for gas exchange to occur but is not the actual mechanism of gas exchange itself.