Who were the contributing scientists that discovered how muscle contraction worked

Andrew Huxley and Niedergerke are the scientists that discovered the sliding filament theory.  

They said that the muscle filaments are made up of proteins like actin and myosin. Actin is the thinner protein that is formed of two subunits – G actin and the F actin. They together form the actin filament.

Myosin filament is formed of the units Heavy meromyosin and light meromyosin. These together make the myosin filament. These filaments slide over each other and attach themselves to make the muscle contract.  

a. by using fur or clothes to trap heat energy near the body

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.