What are single dumbbells that are held independently in each hand

Explain to someone who knows nothing about fossils the study of invertebrate paleontology and how it scientists understand the history of the earth. be sure your explanation contains a minimum of two complete sentences.

Aballet student who learns with the of his instructor is demonstrating learning.

Free runners jump long distances and land on the ground or a wall. how do they apply newton’s second law to lessen the force of impact?