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SingaporeBiology

Homeostasis, Excretion and Coordination

4 dot points across 4 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How does the body remove waste, and how does the kidney clean the blood?

Explain excretion and describe how the kidney filters the blood and reabsorbs useful substances
A focused answer to the O-Level Biology outcome on excretion. The meaning of excretion, the waste products removed, and how the kidney filters the blood and reabsorbs useful substances to make urine.
8 min answer →

How does the body keep its internal conditions steady, such as the level of glucose in the blood?

Define homeostasis and explain the control of blood glucose by insulin and glucagon
A focused answer to the O-Level Biology outcome on homeostasis. The definition, the principle of negative feedback, and how insulin and glucagon control the level of glucose in the blood.
8 min answer →

How do hormones coordinate the body, and how is this different from nervous control?

Describe hormonal coordination and compare it with nervous control, using adrenaline as an example
A focused answer to the O-Level Biology outcome on hormonal coordination. What a hormone is, how the endocrine system works, the effects of adrenaline, and how hormonal control compares with nervous control.
8 min answer →

How does the nervous system let the body respond quickly to its surroundings?

Describe the nervous system and explain the reflex arc as a fast, automatic response
A focused answer to the O-Level Biology outcome on nervous coordination. The central and peripheral nervous systems, the three types of neurone, and the reflex arc as a rapid automatic response.
8 min answer →