ATI TEAS Practice Science Test

Correct Answer: C

Rationale: The correct answer is C: Chromosome. A chromosome is a rod-shaped structure formed when a single DNA molecule and its associated proteins coil tightly before cell division. This coiling helps to compact the DNA and ensure it is evenly distributed to daughter cells during cell division. Centromere (A) is a specific region of a chromosome where sister chromatids are joined. Chromatid (B) refers to one of the two identical copies of a chromosome that are joined at the centromere. Gene (D) is a segment of DNA that carries the genetic information for a specific trait. Therefore, the correct answer is chromosome as it specifically describes the rod-shaped structure formed during cell division due to the coiling of DNA and proteins.

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: C

Rationale: The correct answer is C: Flexor. Flexor muscles are responsible for bending a joint by decreasing the angle between the bones they act upon. They contract to bring two body parts closer together. Cardiac muscles (A) are found in the heart and control its pumping action. Extension (B) refers to the straightening of a joint, not bending. Smooth muscles (D) are found in various organs and are not directly involved in joint movement. Therefore, the flexor muscle (C) is the correct choice for causing a joint to bend.

Correct Answer: C

Rationale: The correct answer is C: Paracrine. This is because somatostatin is a chemical signal that acts locally on neighboring cells within the pancreas to inhibit insulin secretion. Paracrine signals are released by one cell and act on nearby cells of the same tissue. Autocrine signals act on the same cell that produced them, which is not the case here. Neuromodulators modulate the activity of neurons, not endocrine cells like in this scenario. Pheromones are chemical signals that are used for communication between individuals of the same species, not within the same organism like in this case.

Correct Answer: C

Rationale: The correct answer is C: Chromosome. A chromosome is a rod-shaped structure formed when a single DNA molecule and its associated proteins coil tightly before cell division. This coiling helps to compact the DNA and ensure it is evenly distributed to daughter cells during cell division. Centromere (A) is a specific region of a chromosome where sister chromatids are joined. Chromatid (B) refers to one of the two identical copies of a chromosome that are joined at the centromere. Gene (D) is a segment of DNA that carries the genetic information for a specific trait. Therefore, the correct answer is chromosome as it specifically describes the rod-shaped structure formed during cell division due to the coiling of DNA and proteins.