Enzymes.
Enzymes are responsible to make reactions hard to take place, or even very unlikely to happen, to actually happen. They are proteins that have normally an active binding site where molecules may connect to and preform the reaction. The necessary energy to make a reaction occur is less when aided by enzymes and that's what makes of them catalysts so that reactions may occur even when in lower temperatures.
I think the answer should be B as well hope it helps
Answer:
D- Iron
~+lil more info!+~
Iron is the ultimate nuclear “ash,” from which no nuclear energy can be extracted.
1)magnification goes by 10x (read 10 times), 100x,1000x and some goes 10,000x
2)Always focus first using lowest power possible first, switch to medium power (100x) after it's focused on low power(10x), on 100x, use the small knob to focus it more. DO NOT touch the bigger nob when in medium or high power. Switch to high power (100x) when it is focused on medium power, again focus again using the small knob on high power.
3) So it doesn't gather dust and fog up the lense? that one should be self explanatory
