ATI TEAS Science

Correct Answer: A

Rationale: The correct answer is A: DNA mutation. An alteration in the normal gene sequence is referred to as a mutation, which can result from changes in the DNA sequence. Mutations can lead to variations in genetic information. Gene migration (B) refers to the movement of genes between populations. Polygenic inheritance (C) involves the contribution of multiple genes to a trait. Incomplete dominance (D) is a genetic pattern where the phenotype of a heterozygous individual is intermediate between the two homozygous phenotypes.

Correct Answer: D

Rationale: The correct answer is D because bones are resistant to shattering due to the intricate balance of minerals like calcium and phosphorus, along with collagen fibers. Calcium salts alone (choice A) only provide hardness, not flexibility. Collagen fibers (choice B) provide strength but not hardness. Bone marrow and blood vessels (choice C) support bone health but don't contribute directly to resistance to shattering. The combination of minerals and collagen fibers in choice D provides both hardness and flexibility, making bones resistant to shattering.

Correct Answer: B

Rationale: The final phase of mitosis is Telophase. In Telophase, the nuclear envelope reforms around the separated chromatids, chromosomes unwind into chromatin, and the nucleolus reappears. This marks the end of nuclear division. Prophase is the initial phase where chromosomes condense. Anaphase is when chromatids separate and move to opposite poles. Metaphase is when chromatids align at the center. Telophase is the only phase where the nuclear envelope reforms and the nuclear division is completed.

Correct Answer: A

Rationale: The correct answer is A: Merkel's discs. Merkel's discs are located in the epidermis and respond to light touch and slower vibrations due to their sensitivity to sustained pressure. Pacinian corpuscles (B) detect deep pressure and fast vibrations. Meissner's corpuscles (C) are responsible for detecting light touch but not vibrations. Ruffini endings (D) respond to skin stretch and warmth but not specifically to light touch and slower vibrations. Therefore, Merkel's discs are the most appropriate choice for receptors that respond to light touch and slower vibrations.

Correct Answer: A

Rationale: The correct answer is A: A plasma membrane. Both prokaryotes and eukaryotes have a plasma membrane as their outer boundary. The plasma membrane is essential for maintaining cell integrity, controlling the passage of molecules in and out of the cell, and facilitating communication with the external environment. Prokaryotes lack a nucleus enclosed by a membrane (choice B), which is a defining feature of eukaryotic cells. Eukaryotes have organelles (choice C) that are membrane-bound structures, unlike prokaryotes that lack membrane-bound organelles. A nucleoid (choice D) is a region in prokaryotic cells where the genetic material is located, but it is not enclosed by a membrane like the nucleus in eukaryotic cells.