HAIR ANALYSIS An investigator is excited to find a hair with the follicle attached when searching for evidence at a crime scene. Explain why the investigator might be excited.

Organisms within a population must compete for resources to survive

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.

Four types of motile cells in human body?