ATI TEAS 7 Science

Correct Answer: D

Rationale: The correct answer is D: Pancreas. The pancreas produces insulin and glucagon, which are hormones involved in regulating blood sugar levels. Insulin helps lower blood sugar levels, while glucagon helps raise them. The salivary glands (A) produce saliva for digestion, the liver (B) plays a role in metabolism and detoxification, and the gallbladder (C) stores and releases bile to aid in digestion. Therefore, the pancreas is the correct organ responsible for producing insulin and glucagon.

Correct Answer: C

Rationale: The primary function of the lymphatic system is to fight infection and remove excess fluid. Lymph nodes contain white blood cells that help fight pathogens. Lymphatic vessels collect excess fluid from tissues and transport it back to the bloodstream, aiding in immune response. Other choices are incorrect because A: Oxygen transport is primarily done by the circulatory system, B: Blood filtration is mainly carried out by the kidneys, and D: Hormone transport is primarily through the circulatory system.

Correct Answer: A

Rationale: The correct answer is A: Neuron. Neurons are the fundamental unit of the nervous system because they are specialized cells that transmit information through electrical and chemical signals. Neurons have a unique structure with dendrites, cell body, and axon, allowing them to receive, process, and transmit signals. Nerves (B) are bundles of neurons, ganglia (C) are clusters of neuron cell bodies, and neuroglia (D) are support cells in the nervous system. Neurons are the primary functional unit responsible for communication in the nervous system.

Correct Answer: D

Rationale: The correct answer is D: tRNA. Transfer RNA (tRNA) carries amino acids to ribosomes during protein synthesis. tRNA has an anticodon that pairs with the mRNA codon, ensuring the correct amino acid is added to the growing polypeptide chain. A: DNA carries genetic information but does not directly participate in protein synthesis. B: mRNA carries the genetic information from DNA to the ribosomes but does not carry amino acids. C: rRNA is a structural component of ribosomes and helps in protein synthesis but does not carry amino acids to the ribosomes.

Correct Answer: A

Rationale: The P wave on an ECG represents atrial depolarization. During the cardiac cycle, the electrical impulse originates in the sinoatrial (SA) node, causing the atria to contract. This depolarization of the atria is reflected as the P wave on the ECG. This occurs before the ventricles depolarize (choice B), repolarize (choice D), or before the atria repolarize (choice C). Therefore, the correct answer is A because the P wave specifically represents atrial depolarization in the cardiac cycle.