Answer: B represents an element.
Answer:The colonization of Mars has received interest from public space agencies and private corporations and has received extensive hypothetical treatment in science fiction writing, film, and art.
Explanation:
Physical properties are those which can be observed without any change in composition of the substance. Hence, a is the answer.
Answer:
Regularly test the water in residents' homes.
Explanation:
The only way to know if tap water contains lead is to do tests to determine the levels of that metal in the water. Therefore, the state is under an obligation to constantly conduct such tests in the resident´s homes and thus determine whether the water supplied is fit for human consumption.
The state after the tests must guarantee the population the treatment of the water to reduce the levels of lead. The main pipes that contain lead pipes must be changed, as well as those parts of the service connections made of lead.