How does tan build a central idea of her story in the excerpt .

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

Earth takes in thermal energy from the sun in a process called . sunlight strikes earth’s surface at different angles. this angle is called the angle of . btw its

When do you think it’s best to take the psat (what grade year / when in the year)?