65 million years ago there was a mass extinction that is best known for killing the dinosaurs. there was also a large deposit of dust that contained substances only found in asteroids. what most likely killed off the dinosaurs?
an asteroid impact caused the sun to be blocked.
they were crushed by an asteroid.
the water supplies were polluted.
mammals evolved to be better competitors

Positrons are spontaneously emitted from the nuclei of

10 points! will mark brainiest! in a heat engine if 1,000 j of heat enters the system and the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2,000 j 1: write the equation 2: list out your known variables 3: plug the numbers into the equations 4: solve 5: write your solution statement that includes initial energy and final energy added you so much!

Each neuron shown in this figure innervates a group of muscle fibers. what is the term for a group of muscle fibers innervated by a single neuron?