Question

read the text.
in lower-income countries, the high cost of medical equipment, such as microscopes, is often an obstacle to providing health care. stanford university professor manu prakash came up with a simple answer: he created foldscope, a microscope made almost completely of paper that costs less than a dollar. other equipment, such as centrifuges, needs electricity to operate. centrifuges spin blood samples to diagnose infections like malaria. to improve health care access in areas without electricity, prakash invented the paperfuge. the paperfuge is a centrifuge made of paper and string. it costs about twenty cents and doesnt require electricity.
match the problems with their solutions.
prakash invented a version made mostly of paper.
prakash invented a version made of paper and string.
problem
microscopes are expensive.
centrifuges are expensive and need electricity.
solution

Explanation:

The text mentions that microscopes are expensive and the solution for this is Foldscope (a microscope made almost completely of paper). Also, centrifuges are expensive and need electricity, and the solution is Paperfuge (a centrifuge made of paper and string).

Answer:

Microscopes are expensive. - Prakash invented a version made mostly of paper.
Centrifuges are expensive and need electricity. - Prakash invented a version made of paper and string.