Jillian is mapping her co-worker's reasoning process. She puts a few words in brackets. What do the braces signify about the words they enclose?.

Which of the following is s good strategy to use when preparing to take notes in class

Layer r contains a well-known index fossil that is 100 million years old. based on this information and the principle of superposition, a. layers t and m are older than 100 million years, and layers x and g are younger than 100 million years. b. layers t, m, x, and g are all older than 100 million years. c. layers t and m are younger than 100 million years, and layers x and g are older than 100 million years.

Certain gases in air are important natural resources that are used in welding. two of these gases are a. oxygen and argon b. hydrogen and fluorine c. chlorine and sulfur dioxide d. nitrogen and carbon dioxide