If a repressor protein attaches to the operator, RNA polymerase cannot proceed to transcribe key enzymes needed by the organism. This can be seen in the trp operon in E .coli bacteria.
Chemical energy...................
The best way for adolescent to build and protect his or her bones is to ingest food products that are rich in calcium for it is known to make bones stronger. Another way is to be able to do exercise as a daily routine so that the bones are exercised every day to prevent bone disease, this will stenghten the bones and make them more stronger.
There is no man-made objects such as houses or cars that inhabit the atmosphere. Other than satellites of course but they don't count towards that.
