What is direct evidence? another name? an example?

Which sentences describe disadvantages of burning fossil fuels instead of using hydrogen fuel cells? burning fossil fuels contributes to climate change. burning fossil fuels takes place inside expensive fuel cells. fossil fuels aren't widely available, but pure hydrogen is. fossil fuels are nonrenewable.

In a load, the load is paralel to the shaft. n a. angular n b. thrust n c radial n d. none of the above

Which type of microscope would allow the viewer to see ribosomes inside a cell?