PLZ HELP I WILL GIVE BRAINLIESTWhich of the following statements is true? The ratio of work output to work input is always less than one. Only a few machines are 100 percent efficient. Efficiency is calculated by multiplying work input and work output. Some machines are frictionless.

The phlogiston theory in the 17th century attempted to explain burning. the theory stated that combustable objects contained a material called phlogiston, a substance without mass, color, odor, etc. after objects burned, the objects were dephlogistonated and were then in their true form. the phlogiston theory was accepted until the 18th century, when lavoisier proved that combustion requires a gas that has mass. phlogiston is considered a) to be scientific knowledge b) not to be scientific knowledge c) to be proven by scientific method d) to be accepted in the modern scientific community

What is the role of fadh2 in cellular respiration

Which best describes an adaptation that could be found in a fish that lives in a slow-flowing stream? the ability to attract prey by glowingextra gills, for oxygen extractionthe ability to grow largerextra fat, for warmth