It's something to do with the fact that having sickle cell anaemia reduces the chances of contracting malaria, obviously a very common disease in Africa. I'm not quite sure what the link is but hopefully this helps a little bit?
He will use any form of length measurement to measure the length, width, and height of the pool, use the formula V=lwh to find the volume.
The correct answer for this question is: "<span>B) kidneys clean the blood by filtering it to remove wastes." Kidneys clean the blood by filtering it and removing the waste.
The correct answer for this question is: "</span><span>A) secretes excess water as sweat." The role of the skin in the excretory system is to secrete waste and excess water as sweat.</span>
They are not afraid but they try and avoid getting wet because they cannot fly when wet