Structure of a sentence with a Conjunctive adverb.

1.-Chemicals can help foods grow;
2.-The population is increasing.
3.-Fossil fuels can pollute.
4.-Solar power is renewable:
5.-Recycling saves resources;
The population is growing every day.________________scientists are seeking new sources of energy.
Nuclear power does not cause air pollution;_______nuclear power can be dangerous in other ways.
Much of the leftover material from nuclear plants is radioactive._________it can be dangerous for centuries.
Renewable energy holds great promise._________many corporations are investing in it: