Top answers


Why do the muscles of the Iris contract and relax?

To alter the size of the pupil, so the correct intensity of light is allowed through. Enough light is let through to allow clear vision, but not so much light that the retina might become damaged.
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Answered by Calum M. Biology tutor
9530 Views

What are the differences between mitosis and meiosis?

Mitosis and meiosis refer to the way cells reproduce. Mitosis sees the cell divide in two, forming two genetically identical diploid cells. The reproduction of cells means mitosis is used by the body for gro...
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Answered by Chris W. Biology tutor
24298 Views

Describe adaptations of plants that live in dry conditions, such as the desert.

Plants that live in these areas need to minimise the rate at which they transpire in order to preserve as much water as possible. One way they do this is by reducing their surface area:volume ratio, in many ...
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Answered by Emily B. Biology tutor
52228 Views

What is the structure and role of a chloroplast?

The chloroplast has a cell membrane like most cells/organelles. They are long and oval shaped with a similar shape/size to bacteria. Inside the organelle, the grana stack up like disks on top of one another....
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Answered by Adam W. Biology tutor
5751 Views

How do white blood cells protect the body?

White blood cells in the body can attack pathogens, which are micro-organisms which cause disease. The white blood cells can ingest the pathogen, produce antibodies which destroy a particular pathogen, or pr...
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Answered by Eleanor M. Biology tutor
12478 Views