Kno₃ + h₂co₃ → k₂co₃ + hno₃

balance the equation and add the coefficients on both sides, . or, show me how, cause i don't understand this at all and i really, really need a good grade!

To balance an equation you need to end up with the same number of atoms of each element on each side. To start we could try balancing the potassium (K) atoms by making the first compound 2KNO3. Because we have two hydrogens on the left side we need to make the last compound 2HNO3. Because the number of NO3s and CO3s is now equal on both sides, the balanced equation is 2KNO3 + H2CO3 --> K2CO3 + 2HNO3

They are like other investigations? say there was a murder u have to do blood test and finger prints which run through a lab. 

A. ​it generates energy from carbohydrates.b. it requires activation by oxygen.​c. ​it is used by cells to dispose of excess electrons