Pls can someone answer this asap..the outer layer of a young stem undergo changes when it becomes a tree. do you agree with this? justify

The gene that causes sickle-cell disease is present in a higher percentage of residents of sub-saharan africa than among those of african descent living in the united states. even though this gene causes sickle-cell disease, it also provides some protection from malaria, a serious disease that is widespread in sub-saharan africa but absent in the united states. discuss an evolutionary process that could account for the different percentages of the sickle-cell gene among residents of the two regions.

What is the answer for the complicated molecules that make up living things usually contain carbon. why is carbon so important in these molecules?

“in 1492 columbus sailed the ocean blue” is an example of: a)explicit memory b) procedural memory c) semantic memory d)episodic memory