Pls help, I really dont get this.

If t=tall and t=short what will be the physical appearance of the offspring the cross below? a.some will be tall and some will be short b.they will all be tall c.they will all be short d.they will be medium height

Abird flies by moving its wings up and down. which two systems are most directly responsible for the movement of a bird's wings? a. skeletal and muscular systems b. respiratory and muscular systems c. skeletal and digestive systems d. respiratory and digestive systems

How is the expression of surface antigens on red blood cells determined?