CSET CSET Subtest II Life Sciences 3 — Questions and Answers
Question 1: Which blood vessel carries oxygenated blood away from the heart to the body?
- Pulmonary vein
- Pulmonary artery
- Aorta (Correct answer)
- Vena cava
Correct answer: Aorta
The aorta is the largest artery and carries oxygenated blood from the left ventricle to the systemic circulation.
Question 2: What is the term for the maintained internal stability of an organism's physiological conditions?
- Metabolism
- Homeostasis (Correct answer)
- Osmoregulation
- Thermoregulation
Correct answer: Homeostasis
Homeostasis refers to the processes by which organisms maintain a stable internal environment despite external changes.
Question 3: Which plant tissue is primarily responsible for transporting water and minerals from roots to leaves?
- Phloem
- Parenchyma
- Xylem (Correct answer)
- Collenchyma
Correct answer: Xylem
Xylem is the vascular tissue that conducts water and dissolved minerals upward from roots through the plant.
Question 4: A population of bacteria doubles every 20 minutes. Starting with 100 bacteria, how many will there be after 1 hour?
- 200
- 400
- 600
- 800 (Correct answer)
Correct answer: 800
After 1 hour (3 doublings), the population is 100 × 2³ = 800 bacteria.
Question 5: Which hormone signals the kidneys to reabsorb more water, reducing urine output?
- Aldosterone
- Antidiuretic hormone (ADH) (Correct answer)
- Cortisol
- Glucagon
Correct answer: Antidiuretic hormone (ADH)
ADH (vasopressin) acts on the collecting ducts of the kidney to increase water reabsorption.
Question 6: In a food web, which trophic level contains organisms that eat primary consumers?
- Producers
- Primary consumers
- Secondary consumers (Correct answer)
- Decomposers
Correct answer: Secondary consumers
Secondary consumers eat primary consumers (herbivores) and occupy the third trophic level.
Question 7: What is the function of the myelin sheath surrounding some nerve axons?
- Produce neurotransmitters for signal transmission
- Speed up the conduction of electrical impulses (Correct answer)
- Store calcium ions for muscle contraction
- Synthesize new neurons after injury
Correct answer: Speed up the conduction of electrical impulses
The myelin sheath insulates axons and enables saltatory conduction, greatly increasing impulse speed.
CSET CSET Subtest II Life Sciences 3
Which blood vessel carries oxygenated blood away from the heart to the body?