Which of the following is true statement about isotopes?

a.
the number of protons always equals the number of neutrons in all isotopes.

b.
the number of protons never equals the number of neutrons in an isotope.

c.
different isotopes for the same element will always have the same numbers of neutrons.

d.
different isotopes for the same element always have the same number of protons.

The arrival of in the early days of europa’s existence could have formed its ocean. it is likely that the water experienced similar to earth. it is also possible that this water is retained beneath europa’s surface and in its atmosphere due to europa’s . 1.) a. precipitation b. water vapor c. icy debris 2.) a. gravitational compression b. biochemical cycling c. radiogenic heating 3.) a, gravity b. magnetic field c. heat energy for plato

The two stars in a certain binary star system move in circular orbits. the first star, alpha, has an orbital speed of 36 km/s. the second star, beta, has an orbital speed of 12 km/s. the orbital period is 137 d. a) what is the mass of the star alpha? b) what is the mass of the star beta?

When using the scientist method, which step comes last?