Why are synovial joints have greater flexibility than fixed and cartilaginous joint?

Sam is a four-year-old child. as compared to other boys of his age, his skin looks dull. his hair appears damaged and dry. which nutrient is sam’s body likely lacking? a. proteins b. carbohydrates c. fats d. minerals

The amount of oxygen that is actually used by the body during the rest or a hand workout is determined by the heart rate, the stroke volume, and the amount of a. blood circulating in the vascular system b. oxygen removed from the vascular system c. oxygen provided to the vascular system d. blood that individual has in the body e. hemoglobin in the red blood cells

How could natural selection best be used to explain the evolution of the white fur of arctic fox