Brass gets discoloured in air because of the presence of which of the following gases in air?
a. oxygen
b. hydrogen sulphide
c. carbon dioxide
d. nitrogen

Which statement about relative potential energy of electrons is correct? a. an electron in the 2 p orbital of the second electron shell has more potential energy than an electron in the 2 s orbital of the second electron shell. b. an electron in the 2 p orbital of the second electron shell has more potential energy than an electron in the 3 p orbital of the third electron shell. c. an electron in the 3 p orbital of the third electron shell has more potential energy than an electron in the 2 p orbital of the second electron shell.

Hydroelectric uses moving water to do work such as grinding grains in a mill true or false

Which of these structures are found in both plant ans animal cells?