What are 2 difference forms of a single gene called

How to solve 4 nh3(g) + 5 o2(g) > 4 no(g) + 6 h2o(g) in chemistry

Atrain travels 74 kilometers in 3 hours, and then 81 kilometers in 5 hours. what is its average speed?

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.