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Describe and explain how the human lungs are adapted for efficient gas exchange (3 marks)

There are millions of alveoli (gas exchange surface), so they have a very large surface area collectively, which is further increased by having a folded membrane. A larger surface areas means there is a fast...
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What are the innate and adaptive immune systems and how do their roles overlap?

In our bodies we have a host of cells that make up our immune system. The immune system itself can be divided into the innate and adaptive immune response. If we use an analogy, the innate immune system acts...
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Describe how proteins are processed and released from cells

Proteins travel to the Golgi Apparatus where they are modified (e.g. glycosylation) and packaged into vesicles. Vesicles then travel to, and fuse with, the cell surface membrane. This causes the release of p...
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Answered by Shahmeer H. • Biology tutor
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As the volume of blood in the ventricles of the heart increases, with all other factors constant, stroke volume increases till a point. Explain why. (5)

Define stroke volume as the volume of blood expelled by the left ventricle into the aorta per contraction of the heart.Idea that as blood volume in the ventricle increases, this stretches the sarcomeres of c...
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Answered by Azmaeen Z. • Biology tutor
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How can natural selection create two different species from one species?

For speciation to occur, two populations of a species must become reproductively isolated. This can result from either the formation of a geographic barrier between two populations of the species, preventing...
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Answered by Sean K. • Biology tutor
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