How were redi’s and pasteur’s experiments similar?
a both studied the growth of microbes in broth.
b both studied flies emerging from meat.
c both tested the idea of spontaneous generation.
d both tested whether pasteurization kills microorganisms.

The right answer is C Both tested the idea of spontaneous generation.

Spontaneous generation is an Aristotelian notion that has fallen into disuse, making the assumption of the appearance without ascendants of living beings from inanimate matter. This notion is similar to the modern conception of abiogenesis.

It was challenged by scientists who had carried out experiments in the seventeenth century, such as the Italian naturalist Francesco Redi. It was not until the nineteenth century, when it also took the name of "spontéparité" or "heterogenie", so that it is invalidated by Pasteur with the experience of his gooseneck balloons and his discovery of pasteurization, as well as the experiences of John Tyndall. It was then replaced by microbial theory and cell theory.

it's c. (to reduce the greenhouse effect/carbon gasses)