Increasing excitatory signals above threshold levels for neural activation will not affect the intensity of an action potential. this indicates that the reaction of a neuron is: (2 points)

inhibited by the myelin sheath

delayed by the refractory period

an all-or-none response

independent of the repolarization

dependent on neurotransmitter molecules

There is a theory that indicates that dinosaurs became extinct when about 65 million years ago, a large asteroid hit the earth surface. dust caused by this collision blocked the sunlight reaching the earth's surface and many forms of life became extinct due to the cold. fearing this threat, how large the radius of an asteroid should you be looking for if the dangerous asteroid size is approximately the same as the one that killed the dinosaurs? available data suggests that about 18% of that asteroid's mass ended up as a dust spread evenly over earth after eventually settling out of the upper atmosphere. about 0.0180 g/cm^2 of dust, which is chemically different than the earth's rock, covered the earth's surface. typical asteroids have a density of about 1.9 g/cm^3. now that we know the size of the asteroid, how much energy was released during impact, assuming all of it was just the kinetic energy of the asteroid right before the impact?

For the car in the picture ,in which direction is the normal force? -into the screen -down -out of the screen -up

The radius of an atom is closest in size to a