The main difference between population and community is that a population is a group of individuals of a particular species living in a particular ecosystem at a particular time whereas a community is a collection of populations living in a particular ecosystem at a particular time.
I would say its the first option. Hope this helped.
Nuclear energy is generated by initiating a process called nuclear fission (the splitting of atoms). Very large atoms like Uranium are unstable and release a lot of energy when split apart. They also release neutrons which will then fly around and split up other uranium atoms, releasing more energy and more neutrons and the cycle continues. This chain reaction generates A LOT of energy. The energy is then used to heat up water into steam. The steam flows through pipes and into a turbine, spinning the turbine around (just like wind does to a wind mill). As the turbine spins around it powers a generator to create electricity, which can then be harnessed and distributed.
The answer is the sun has already set leaving darkness. During the time the satellite image was taken, the sunset was taking place across the eastern third of the U.S. and Canada. Cloud conditions were seen from western regions of the U.S., Canada, Texas, and Gulf of Mexico because the sun has not yet set in these areas.
