the ages of rocks can be determined using the isotope 135cs, which undergoes beta decay with a half-life of 2.3×106 y. a rock sample contains a ratio of 135ba to 135cs of 0.15. given that 135ba is a stable product of the beta decay of 135cs, and assuming there was originally no 135ba present in the rocks, calculate the age of the rock sample.

How long must a student wait for feedback on how they did on the accuplacer? a. 1 day b. 1 week c. 1 month d. immediate feedback (no wait)

Name and describe how to implement one method of embellishment.

In the image, layer a is the topmost layer. layer c contains fossils from the precambrian era. layer b contains dinosaur fossils, and layer a contains fossils of mammals. which two statements are supported by this evidence? 1. mammals lived before the precambrian era. 2. dinosaurs and mammals existed in the precambrian era. 3. dinosaurs evolved after precambrian organisms. 4. precambrian organisms evolved after dinosaurs. 5. precambrian organisms were the first life-forms to become fossilized, according to this sample.