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Biology
GCSE

What are tropisms?

A tropism is a growth in a plant in response to a stimulus. The stimulus could be a change in the direction of light or a water source. To recap, a stimulus is a change in the environment of an organism t...

HP
Answered by Holly P. Biology tutor
13663 Views

Explain the exchange of oxygen between an alveolus and a capillary.

The blood in the capillary has just returned to the lungs from the rest of the body, so contains a low concentration of oxygen. The alveolus contains air that has just been breathed in by ventilation, so ...

AD
Answered by Anastasia D. Biology tutor
3032 Views

Using a diagram, outline the path the blood takes through the human body, starting with the aorta and identifying the major vessels and chambers of the heart.

Aorta --> systemic circulation [branches in order: coronary artery (to supply the heart), carotid artery (to supply the head), hepatic artery (to supply the liver), mesenteric artery (to supply the gut...

SG
Answered by Sophie G. Biology tutor
2522 Views

Gas exchange happens in the alveoli of the lungs. What are three adaptations of the alveoli that allow for this?

  • Thin alveolar walls for O2 and CO2 to travel through - To travel across the membrane, gases have to be dissolved, so the alveolar walls are moist - Large surface area to volume ratio allows for maxi...
SL
Answered by Sarah L. Biology tutor
3109 Views

What factors affect rate of photosynthesis in a plant?

There are three key factors affecting rate of photosynthesis at GCSE level. They are light intensity, CO2 concentration, and temperature. These factors are best visualised by drawing graphs with rate of p...

KF
Answered by Kieran F. Biology tutor
6672 Views

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