Top answers

Biology
GCSE

What are stable ecosystems? Can you give an example?

A stable ecosystem is where the outputs (losses of the ecosystem) equal the inputs (gains) - there is a balance. They are supported by what they produce, and their structure and function remain constant f...

Answered by Samhitha A. Biology tutor
3215 Views

Give three reasons for why biomass may not be transferred from primary consumers to organisms at higher trophic levels in the food chain. [3 marks]

Some energy is lost via the the primary organism's waste products (such as urine and faeces).Some energy is lost as heat produced as a product of respiration.Energy produced by respiration may be used for...

Answered by Thaarabi T. Biology tutor
10258 Views

In a circuit with a 12V battery, 20Ω resistor and 10Ω resistor, all in series, calculate the current that would flow?

This question can be split into two parts, the first is calculating overall resistance: in series the Rtotal = R1 + R2 so here Rtotal = 10Ω + 20Ω = 30Ω The seco...

Answered by Lauren A. Biology tutor
3910 Views

Humans need to remove (excrete) waste products from the bloodstream. Describe the processes that produce waste products and how the products are removed from the body. (6 marks)

Urea is produced via the breakdown of amino acids in the liver, which is removed from the blood by the kidneys and excreted in urine. Carbon dioxide

Answered by Kizzy J. Biology tutor
19815 Views

An individual is seated in a darkened room. What would you expect their pupils to look like? A light is shone onto their eyes and a change in their pupils is noted, what change would you expect and why?

In dark/dim conditions the human pupil dilates (diameter increases) to allow more light in.In bright conditions the pupil constricts (diameter decreases) and less light enters the eye.This is through a co...

Answered by Tom B. Biology tutor
2012 Views

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