Living Systems Respond to Their Environment

The circulatory system, how the body defends itself, and the genetics behind inherited disease.

9 questions, free, marked as you go with a worked explanation on every one.

What this covers

A heart beats 70 times per minute and pumps 70 mL with each beat. What is the cardiac output in litres per minute?
Which blood component is mainly responsible for fighting infection?
What is the role of antibodies in the immune response?
How does a vaccine produce immunity without causing the disease?
Which factors increase the risk of cardiovascular disease? Select all that apply.
A genetic test can reveal a person's risk of a disease that has no cure. Which ethical concern does this raise most directly?
At rest a person's cardiac output is 5.0 L of blood per minute, and every 100 mL of arterial blood carries about 20 mL of oxygen. How much oxygen does the circulation deliver each minute, in litres?
Blood pumped out of the heart travels through arteries, then arterioles, then capillaries, then venules and veins on the way back. Which statement correctly matches a type of vessel to its structure and its job?
Use the table. Which blood component's main job is fighting infection?