Why is water a polar molecule and Carbon Dioxide is not?

What is important to study for nios grade 12 chemistry? i have only one month left.

The twister and runaway train are two coasters at the same amusement park. both coasters start at the same height. the coaster for the twister is twice the mass of the coaster for the runaway train. which roller coaster has greater gravitational potential energy at the start of the ride?

The organs inside the body and how they function together