If the pressure of a gas is held constant and the volume decreases, what happens to the temperature?

Tempreture increases
Temperature decreases

The big bang nucleosynthesis theory states that elements were produced in the first few minutes of the big bang while elements have their origins in the interiors of stars, forming much later in the history of the universe.

Ineed ! i have no clue how to do this problem.

What is the wavelength of a 3*10^12 hz infrared wave a 3*10^20m b 1* 10^4m c 3*10^-3m d 1*10^-4 m