Answer:
harmful effects
1. that will cause air pollution
2. that will destroy our earth
They are blue because of hydrogen helium and methane
Answer:
the application of scientific knowledge for practical purposes, especially in industry. Another answer:the sum of techniques,skills,methods and processes used in the production of goods or services or in the accomplishment of objectives, such as scientific investigation
G.P.E = mgh
Weight = mg = 200N
So G.P.E = 200 * 2 = 400 Joules