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 reason why nost scientists thought that the first true cells formed on Earth were anaerobic is being shown in the second option :B. because there was no oxygen on early Earth. Paying attention to this fact scientists discovered that first cells were prokaryotes and greatest part of them created oxygen as a toxic by-product of their own metabolism which make them understand how the planet was provided with oxygen and made a conclusion that first cells were anaerobic.
I think it's nucleic acid.
Answer: False
Explanation: Valley glaciers are not known to spread throughout a whole continent. A valley glacier is usually formed within a mountain range. They are fed by ice caps and generally shaped as a narrow ribbon or stream of ice between two valley walls. Valley glaciers are commonly found in Alaska and in parts of the Alps.
