Sickle-cell disease is common in tropical and sub-tropical regions because being a carrier, carrying a single sickle-cell mutation (sickle cell trait), affords some resistance to malaria.
Hello! THere are many differences between a grassland and a savanna. For one, a savanna is a grassland, however, A savanna is usually very dry. A savanna also has very few trees, while grasslands can be plush with many trees. Grasslands could also be in mountains while savannas are vast dryer lands with animals who live in dry weather. Grasslands also contain a lot of water sources like lakes, rivers, ponds, and savannas usually don't. Those are just a few o the many differences between them!
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SuperHelperThingy
<span>C) The emissions of the internal combustion engine which runs on oil/gas has added to air pollution such as smog. </span>
