Answer:
Lakes and rivers provide Canadians not only with drinking water, food, transportation networks and recreational opportunities, but also with hydroelectricity. In fact, Canada is one of few countries around the world to rely on hydropower for more than half of its electricity needs.
Explanation:
Plants need nitrogen in order to grow. Nitrogen is abundant in the earth's atmosphere, but plants cannot use it in that particular form (nitrogen gas). Certain bacteria which reside on some plant roots are able to change atmospheric nitrogen into a form that plants can use (ammonia).
Lac operon gets activated in the presence of lactose, but Trp operon gets deactivated in the presence of tryptophan.
