<span>Darwin essentially argued that living things are engaged in a 'struggle for existence' and that any features they possess which affect their survival and reproductive potential will be subjected to continuous selective pressure. This might be seen as his 'new big idea' in the whole evolution thing. This means that through time those features which confer an advantage in the struggle for life will be retained and those that constitute a handicap will be lost. Not for individuals but for the race. So the composition of the population (or species) changes through time, eventually producing such widely divergent forms that cannot interbreed, and are so called separate species. That is a brief outline of the theory.</span>
It is electron transport chain or simply called as ETC
Answer:
The correct answer is - texture and composition.
Explanation:
The classification of the three types of rocks as igneous, sedimentary, and metamorphic rocks is primarily based upon the components and the texture. The sizes and shapes of grains of the mineral and other components and how they interact are present are known as texture.
Igneous rocks - melted rock deep inside the Earth.
Sedimentary rocks - layers of sand, silt, dead plants, and decomposed organism and their skeletons.
Metamorphic rocks - changed by heat and pressure underground
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?
