4/9+3/9=what is the answer to this problem

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

Type the correct answer in the box. spell all words correctly.what is the correct term for living the most sustainable life you can within your current circumstances? when your are being as sustainable as you can within your current lifestyle, you are said to be sustainability.

The characteristic of two different types of reactions are shown below. reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of and element. which statement is true about the atoms of the elements that participate in the two reactions? a: their identity changes in both reaction a and b. b: their identity changes in reaction a but not b. c: their identity changes in reaction b but not a. d: their identity remains the same.