Answer:
Larger islands that are large and close to the mainland are shos lower rate of extinction due to the fact that the species present have more space so there will be more resources available in comparison to smaller islands where limited space and limited resources available.
Extinction is greater on islands isolated due to the unlikelihood of immigration and as it is opposite to the island close to the mainland and competition is more in isolated islands.
The valves are responsible for preventing blood from flowing in the wrong direction, they are present in the veins, and the arteries don't need them because the aorta (biggest artery) pumps or in other words pushes it with such a force that no other force can change its direction, in the veins there is no structure present for pumping them as a result we have got valves so that they go in one direction...... the meaning of the word valve is to allow in one direction
If the size of a cell increases it will be more difficult (all other things being equal) for diffusion to transport materials out of the cell. Therefore, less of the cell's interior will be able to come in contact with the cell's surface. If less of it comes in contact, less of it can cross the cell membrane.
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