Hi everyone. Please answer these 2 questions. I will mark brainliest

Acetylene is a gas which burns rapidly on its own, and is considered highly explosive. a) true b) false

Technician a says that if a valve is open when a piston rises to the very top of a cylinder, the piston may actually strike the valve head and cause serious engine damage. technician b says if the camshaft is located in the engine block, then the engine is called an overhead valve engine, ohv engine, or an in-block camshaft. who is right? a. b only b. both a and b c. a only d. neither a nor b

Awell-diversified portfolio needs about 20-25 stocks from different categories is this true or false?