it works on the principle of a stream of water coming out of a cylinder which at its lowest part has several horizontal paddles bent in one direction.

How would the previous sentence be correctly capitalized?
Answer: It works on the principle of a stream of water coming out of a cylinder which at its lowest part has several horizontal paddles bent in one direction.
most citizens with functional disorders can get better. however, not all will recover.

How would the previous sentence be correctly capitalized?
Answer: Most citizens with functional disorders can get better. However, not all will recover.
earning my daily keep by helping and hindering in equal proportions aboard the quabbin diver, i travelled into georgetown, grand cayman whilst asleep on the back of a motorbike.

How would the previous sentence be correctly capitalized?
Answer: Earning my daily keep by helping and hindering in equal proportions aboard the Quabbin Diver, I travelled into Georgetown, Grand Cayman whilst asleep on the back of a motorbike.
because of aging, the vitreous gradually shrinks, the immune system may response to protect the retina - this may cause the fibrous membrane to grow.

How would the previous sentence be correctly capitalized?
Answer: Because of aging, the vitreous gradually shrinks, the immune system may response to protect the retina - this may cause the fibrous membrane to grow.