ATI TEAS 7 Science

Correct Answer: C

Rationale: The correct answer is C: Testes. The testes are responsible for producing testosterone, a male sex hormone. They contain specialized cells called Leydig cells that produce testosterone. The adrenal glands (A) produce hormones like cortisol and adrenaline, not testosterone. The pituitary gland (B) regulates hormone production but does not directly produce testosterone. The pancreas (D) produces insulin and other digestive enzymes, not testosterone. Therefore, the testes are the correct answer for testosterone production.

Correct Answer: B

Rationale: The correct answer is B: Skeletal. Skeletal muscles are responsible for voluntary movements because they are attached to bones and are under conscious control. They enable us to move our body parts intentionally. Smooth muscles (A) are involuntary and found in internal organs. Cardiac muscles (C) are also involuntary and specific to the heart. Option D simply defines a term and is not a type of muscle.

Correct Answer: C

Rationale: The correct answer is C: Carries specific amino acids to the ribosomes. tRNA is responsible for carrying specific amino acids to the ribosomes during protein synthesis. It recognizes the codons on mRNA and pairs them with the corresponding amino acids. This process ensures that the correct amino acids are added to the growing polypeptide chain. Choice A is incorrect because tRNA does not transcribe DNA into mRNA; that is the role of RNA polymerase. Choice B is incorrect because decoding the genetic code on mRNA is done by tRNA along with the ribosomes. Choice D is incorrect because tRNA does not modify the structure of proteins; that is typically done by enzymes or post-translational modifications.

Correct Answer: C

Rationale: The correct answer is C: Light energy from the sun. This is because photosynthesis, the process by which plants and other organisms convert light energy into chemical energy, is the primary source of energy in most ecosystems. Sunlight is essential for plants to produce food, which then sustains the entire food chain. Choice A (Chemical energy stored in bonds) is incorrect because this energy is a product of photosynthesis and not the primary source entering ecosystems. Choice B (Thermal energy from the Earth's core) is incorrect as it is not a significant source of energy for most ecosystems. Choice D (Kinetic energy from wind and water) is also incorrect as it is not the primary source of energy entering ecosystems, although it can play a role in some ecosystems.

Correct Answer: C

Rationale: The correct answer is C (2+ or 3+). Iron is a transition metal, meaning it has variable oxidation states. Iron commonly forms cations with charges of 2+ (Fe²⁺) or 3+ (Fe³⁺) due to its ability to lose 2 or 3 electrons, respectively, from its outer shell. This is consistent with the typical behavior of transition metals to exhibit multiple oxidation states. Choices A and B are incorrect because iron does not commonly form cations with charges of 2- or 3-. Choice D is incorrect as iron typically forms cations with a positive charge, not a negative charge.