Sickle cell anemia is caused by an abnormal hemoglobin in red blood cells. hemoglobin is the red pigment found in red blood cells for carrying oxygen.The abnormality arises from a genetic mutation in the DNA gene that codes for the beta chain of the protein called globin of which hemoglobin is made of.In the beta chain, the sixth amino acid called glutamine is replaced by another one called valine.<span>This one change in the amino acids cause the hemoglobin protein to behave abnormally, causing red blood cells to lose their normal spherical shape and become bent like a sickle, hence the name "sickle cell" anemia</span>
Boiling water on a stove is an example of thermal energy. Thermal energy is produced when the atoms and molecules in a substance vibrate faster due to a rise in temperature.
The function of the limb is to help them get around and move. They might be similar in the way they’re structured? I don’t have a picture so I can’t tell. And you can assume that at one point these four animals all shared a common ancestor. Hope I helped!