.............Help on what?
Activation energy is required to start a chemical reaction. Activation energy is the energy needed to allow the reactant to react. Activation energy is measured in Joules (J).
The answer is c. Inside leaves, there's a lot of chloroplast, which contains chlorophyll for photosynthesis. This can make energy.
It is a cold Artic air mass over Siberia. Air masses are altered because it doesn't stay in one place and changes as it moves due to the temperature of environment that can be caused by moisture. The cold Artic Mass from Siberia will go to the North Pole, Canada then moves further to the South area.
