In the lonosphere, the collision that raises the energy levels of oxygen and nitrogen occurs between which of the
following? Select all that apply.
gas atoms
electrons
protons
neutrons

The vaccine in a flu shot contains weakened flu viruses. how does a flu shot work with the immune system? a. it destroys lymphocytes. b. it destroys macrophages. c. it activates macrophages. d. it activates lymphocytes.

Which box will not accelerate? 4 newtons 4 newtons 4 newtons 25 kg 4 newtons 15 newtons 10 kg 30 newtons 40 newtons 50 kg 30 newtons 30 newtons

Which best describes the nucleus of an atom a. it is where all of the particle s of the atom are located b. it is the negatively charged part of the atom c. it is where the electrons and the protons are located d. it is the part of the atom with the greatest mass