Which indicates that an exotérmica chemical reaction occurs when two substances are mixed together ?

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

Which part of a feedback mechanism is able to monitor the conditions outside of cells and usually uses nerve cells to relay this information to an intergrating center

As you watch a surfer ride a wave towards the shoreline, what is the shoreline? a) displacement reference b) reference point c) coordinate plane d) cartesian boundary