There are different types of channels for blood flow that transport the blood pumped by the heart. They greatly differ only in the size of their diameters. Arteries are the big ones that are located mostly near the heart. Veins are the next which is where nurses inject you to gather blood. Then, the smallest ones are the capillaries.
Answer:
The idea of using recycle tires at playgrounds is a concern for some scientists because they contain carcinogenic substances.
Explanation:
Recycle tires are in playgrounds as rubber mulch. This one is on the playground's floor to cushion the impact of any falls that kids may have while playing. The problem with this product is that, as they are old tires cut into little pieces, they still have the tires' toxins such as arsenic, benzene, cadmium, mercury, etc. Exposure to these toxins can cause cancer. This is why some scientists are concerned with this material in areas where kids are exposed to it since they are more vulnerable to carcinogens than adults.
In aluminium fluoride, aluminium carries positive charges so fluoride should carry negative charge to be electrically neutral.So for aluminium ion with three positive charges fluoride ion should possess three negative charges to make aluminium fluoride electrically neutral.
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