Water vapor and carbon dioxide!
Answer:
there's no photo? but I'm willing to help
Answer: 
Explanation:
Given
Discharge is 
Diameter of pipe 
Distance between two ends of pipe 
friction factor 
Average velocity is given by

Pressure difference is given by

Answer:
A benchmark
Explanation:
Most times a benchmark serves as the better measure when assessing a computer's performance, this is because CPU speeds can only evaluate an aspect of a computer's performance whereas a benchmark offers the advantage of measuring all the aspects of a computer's performance for a specific type of computing problem.