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What are the differences between the structure and function of arteries and veins?

Arteries are blood vessels that carry blood away from the heart . They have thicker walls than veins in order to cope with far higher blood pressure levels. Arteries also have a thicker layer of smooth muscl...
WH
Answered by William H. • Biology tutor
10987 Views

Why do humans have a double circulatory system?

Ask the student: what other option is there? What are the differences between the two? Answer: Humans have a small surface area to volume ratio, so diffusion alone is not enough to meet the high metabolic de...
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Answered by Divya V. • Biology tutor
9589 Views

How do I explain the process of Natural Selection?

VOSSAG V - Variation: all organisms undergo varying amounts of genetic variation due to genetic mutations or environmental factors (such as geographic separation). O - Overpopulation: all populations have th...
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Answered by Ben K. • Biology tutor
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How do the components of a plasma membrane affect the movement of substances into and out of a cell, and why is this regulation important?

Phospholipids and proteins regulate the movement of substances through the membrane, thereby allowing the membrane to be selectively permeable . This is important since it allows the cell to, for example, ma...
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Answered by Joy H. • Biology tutor
3954 Views

What is a pathogen?

An organism that causes disease e.g. bacteria, virus
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Answered by Erin W. • Biology tutor
3809 Views