Answer:
Fossil fuels.
Explanation:
A fossil fuel is a fuel obtained from nature such as crude oil, coal, wood etc. The burning of fossil fuels releases tremendous amounts of carbon IV oxide into the environment causing a myraid of environmental problems paramount among them is global warming with its attendant consequences.
Answer:
E. better schools
Explanation:
This contributes the most to human development in his community because it provides children with more resources and better opportunities than a sub-par education system. If a community is able to better their school system, they will begin to see a lot of positive changes in their area.
Answer : The amount of oxygen gas collected are, 0.217 mol
Explanation :
Using ideal gas equation :

where,
P = pressure of gas =
(1 atm = 760 torr)
V = volume of gas = 5 L
T = temperature of gas = 
n = number of moles of gas = ?
R = gas constant = 0.0821 L.atm/mol.K
Now put all the given values in the ideal gas equation, we get:


Thus, the amount of oxygen gas collected are, 0.217 mol