The actual contractile units of muscles extend from z disc to z disc. they are

There are four units of muscles extend from z disc to z disc. They are thick filaments,myofibrils, sarcoplasmic reticulum and sarcomeres. Cross sections of the sarcomere in areas where thick and thin filaments overlap show that thick filament is surrounded by 6 thin filaments - each thin is surrounded by 3 thin

No that answer is wrong. you have written the function of mitochondria in chloroplast and function of chloroplast in mitochondria.

True statement gravity force is more on bigger mass, less on smaller mass.all mass fall on planet with same acceleration and speeds