Read the article " Humans, birds communicate to collaborate" . Choose one of the studies mentioned in the article. What was the researchers’ hypothesis? How did they test their hypothesis?

Which property is used to identify the origin of an igneous rock? color density hardness crystal size

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.

Question#29: why does the tropical ocean have a greater temperature range than the temperate ocean?