<span>The organisms in the soil food chain that don't obtain energy directly from plants are protozoa.
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Hi, your answer is correct.
All alkail metals react with halogens vigorously to produce salt. The alkali metal would loose an electron to form and ion with the halogen
Activation energy is the energy required by reactants to undergo chemical reaction and given products
Every reactant has some internal energy (sum of all kind of energy like kinetic energy, potential energy, mechanical energy, chemical energy etc). It needs some extra energy to undergo chemical reaction which is activation energy
All kinds of reaction whether exothermic or endothermic needs activation energy
Threshold energy = internal energy + activation energy
