What is one purpose for using reciprocating engines

Afixed resistor has the following color bands: orange, red, brown, gold. what is the rated resistance

Iknow this isn't a question, but is there someway to ask a question under public safety or is there no category for it? i don't know if i'm overlooking it or not.

The graph shows a trend in an ecosystem over time caused by increased pollution in the region. what can you conclude from the graph? a. there’s lower biodiversity among birds. b. there’s a higher reproductive rate among birds. c. there’s a significant decline in the number of producers. d. other types of animals were unaffected by pollution.