The second law of thermodynamics states that
when a process converts energy from one form to another, some energy converts into heat, an unusable form of energy
energy can neither be created nor destroyed, but it can change from one form to another
energy flows through ecosystems without being recycled most energy in ecosystems comes from the sun

The correct answer is  (a) when a process converts energy from one form to another, some energy converts into heat, an unusable form of energy.

This means that the 100% energy produced is not converted into the 100% work done some part of that energy is loss in the form of heat.  Example: If a car runs with fuel, engine will only stop once the fuel is over. The car will not run until the fuel is refilled into it. Some of the the energy is released in the form of heat once the car is refilled.

this is more of a statement than a question. is there answers to go along with this, or is it opinion based?

bacteria could be both, harmful and to us. harmful bacteria could make us sick and probably even by getting the chances of getting a disease, but good bacteria fight it off with your immune system. there is always bacteria everywhere we go. we need to make sure to wash our hands after using the restroom, before eating, after eating, after petting an animal too. so you see, bacteria is everywhere and is harmful or . i hope this . : ) : ) : )