question: the diagram below shows the three parts of the manual and how they relate to each other.
Capitalize this past sentence correctly.
A: The diagram below shows the three parts of the manual and how they relate to each other.

question: a number of products (14) were examined for a content of chlorine in the packaging material as an indication that the material was made of pvc.
Capitalize this past sentence correctly.
A: A number of products (14) were examined for a content of chlorine in the packaging material as an indication that the material was made of PVC.

question: concrete foundations, several meters thick, had to be removed and therefore, possibly with a view to saving money, the ministry of defence left the door slightly ajar for a partial conservation of the installation.
Capitalize this past sentence correctly.
A: Concrete foundations, several meters thick, had to be removed and therefore, possibly with a view to saving money, the Ministry of Defence left the door slightly ajar for a partial conservation of the installation.