"The mass of Substance C is five times the mass of Substance B", the given statement is correct.
Answer: Option D
<u>Explanation:</u>
As Jessie added 16 gm. of Substance A to 4 gm. of Substance B Obtained certain amount of Substance C which can be calculated as follows:
amount of Substance C = Substance A + Substance B = 16 + 4 = 20 gm
Therefore, 20 gram of Substance C was obtained. Here, fourth statement is correct which says the mass of Substance C ifs five times the mass of Substance B to justify this, see the below:

Ava is able to do this because of an improvement in selective attention. This is a mechanism to focus on a specific thing in the environment though certain amount of time.
Answer:
No matter in what capacity you are writing a letter of advice, the burden lies on you, to give a positive response. Before responding to such a request you should think about it, but the letter should not be delayed. You should choose your words carefully, do not try to be judgmental. Make the person believe that you really care about him or her and the opinion you are giving is based on the sincerity. If you consider the topic sensitive, you should consider your approach carefully and avoid strong language. Its better to restrict your opinion, to the subject that has been asked do not add other aspects to it.
“Give me liberty or give me death. Words from a speech by Patrick Henry urging the American colonies to revolt against England. Henry spoke only a few weeks before the Revolutionary War began: “Gentlemen may cry Peace, Peace, but there is no peace.
Explanation: