ATI TEAS Science Questions

Correct Answer: A

Rationale: A nucleus always has a positive charge. This is because the nucleus is composed of positively charged protons, along with neutral neutrons. The positive charge of the protons is balanced by the negative charge of the surrounding electrons in an atom, resulting in an overall neutral charge for the atom as a whole. Therefore, choice A is correct as it accurately reflects the positive charge of the nucleus due to the presence of protons. Choices B, C, and D are incorrect because they do not accurately represent the fundamental composition and charge distribution within an atom's nucleus. A stable nucleus consists of positively charged protons and neutral neutrons, leading to an overall positive charge, and not a neutral charge as suggested in the incorrect choices.

Correct Answer: A

Rationale: The correct answer is A: Complement system. The complement system is a vital component of the immune system responsible for destroying pathogens through various mechanisms like promoting inflammation, enhancing phagocytosis, and directly lysing pathogens. Fibrinogen is crucial for blood clotting, the major histocompatibility complex is involved in immune responses, and platelets aid in blood clotting and wound healing. However, none of these directly destroy pathogens as the complement system does.

Correct Answer: B

Rationale: The correct answer is B: Capillaries. Capillaries are the smallest blood vessels that connect arterioles (small arteries) with venules (small veins). They enable the exchange of oxygen, nutrients, and waste products between the blood and tissues. Arterioles are small arteries that carry blood away from the heart, while venules are small veins that carry blood towards the heart. Veins are larger blood vessels that transport blood back to the heart. Therefore, capillaries specifically serve as the vessels responsible for the exchange of substances between the blood and body tissues.

Correct Answer: C

Rationale: The correct answer is C. The ovaries are responsible for producing eggs (ova) and hormones (estrogen and progesterone). They are essential for reproduction, including the release of eggs for fertilization and for regulating the menstrual cycle. The fallopian tubes, as mentioned in choice A, transport eggs from the ovaries to the uterus for potential fertilization. The vagina, described in choice B, serves as the birth canal and also connects the uterus to the external environment. The cervix, as stated in choice D, is the lower part of the uterus that connects it to the vagina and also plays a role in protecting the uterus from infections and serving as a passage for menstrual flow.

Correct Answer: B

Rationale: The small intestine is the primary site where the absorption of nutrients from digested food occurs. Its large surface area, specialized cells, and villi play key roles in maximizing nutrient absorption, making it the structure in the digestive system that absorbs the most nutrients. The stomach's main function is to break down food with acid and enzymes, not absorb nutrients. The large intestine primarily absorbs water and electrolytes, not nutrients. The esophagus is a muscular tube that connects the throat with the stomach and does not play a role in nutrient absorption.