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Explain how smooth muscle in the arterioles can reduce blood flow.

The smooth muscle contracts, causing vasoconstriction. Vasoconstriction is the narrowing of the vessel lumen.
HA
Answered by Hannah A. • Biology tutor
10815 Views

why does vision using the fovea have high visual acuity, but low sensitivity to light compared with vision using other parts of the retina.

the connections within the retina explain this. there is a different density and distribution of different types of cells in the retina - the fovea, in the centre of the eye, has a high density of cone cells...
JW
Answered by Juliette W. • Biology tutor
9879 Views

what is a test cross used for and how do you know what genotypes to cross?

A test cross is used to discover the genotype of an individual by crossing two parents to see the phenoypic ratio of the offspring produced. A homozygous recessive individual (one with two recessive or small...
ER
Answered by Emily R. • Biology tutor
21528 Views

How should I structure my biology essay?

Mark schemes for biology essays in AQA aren't like the six mark questions at GCSE. You have to cover the subject broadly at first and show that you have an overall understanding of the tpoic in question befo...
SS
Answered by Samriddhi S. • Biology tutor
7479 Views

A plant community on an extinct volcano displays the process of succession. Explain why there would be very few species at the end of the eruptive life cycle of the volcano and why rate of new species introduction would rapidly increase afterwards.

The initial environment would be a harsh/hostile environment which few species would be adapted to. The volcanic rock would have to be broken down to form humus, only a little or none would have been availab...
NM
Answered by Nehemie M. • Biology tutor
3494 Views