50 points welp Which best describes the movement through the nephron?

Blood is passed into the nephron and removed through the urethra.
All materials that exit the blood into the nephron are removed in the urine.
Some of the materials that exit the blood can be returned to the blood.
High quantities of sugars and water are excreted in the urine.

How many trophic levels are there in the following food chain? phytoplankton - shrimp - perch - pike - osprey

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.

One gene can influence trait(s). one trait can be determined by gene(s).