Help plz what is 2 x 9

Scientists observed a rock stratum with fossil. if mollusks evolved before arthropod, where will their fossils be found.

What is one reason students take sat subject tests

Classify each action depending on whether it will meet or fail to meet the goals of the organization. a group of students form a healthy earth club at their school. their goal is to limit their school’s impact on human-led climate change. they brainstormed a list of actions they can take to meet this goal.