why the frequency of sickle cell trait is so much higher in sub-Saharan Africa than in most other parts of the world?

Which sentence best describes the relationship between chlorophyll and the chloroplast? a.) chlorophyll is a chemical found in a chloroplast. b.) chloroplast is a chemical found in a chlorophyll. c.) both chlorophyll and chloroplasts are found in animals. d.) both chlorophyll and chloroplasts make carbon dioxide.

What condition is kept close to its set point in osmoregulation? a. body temperature b. platelet count c. blood glucose level d. water balance

Which was most likely an effect on society that resulted from improvements in blood handling during world war i and world war ii?