Getting enough rest and eating healthy foods to maintain a healthy immune system.

That statement is true

The strength of our immune system is determined by our white blood cells.

Getting enough rest will make our blood cells regenerate faster ,  and eating healthy foods ( especially those that are rich in vitamin C) will increase the productivity of our white blood cells

Habit 1: be proactive  habit 2: begin with the end in mind  habit 3: put first things first  habit 4: think win-win  habit 5: seek first to understand, then to be understood  habit 6: synergize  habit 7: sharpen the saw 

Hyper extension is the extension of a limb/body part beyond its limits