Calcium has an atomic number of 20 and an atomic mass (weight) of 40. Therefore, we know that calcium has 20 protons
40 protons
40 electrons
20 neutrons
20 electrons

select all that apply

the ozone layer acts as a filter for the shorter wavelength and highly hazardous ultraviolet radiation (uvr) from the sun, protecting life on earth from its potentially harmful effects. when the sky is clear, there is an inverse relationship between stratospheric ozone and solar uvr measured at the earth's surface.

pie chart because it is in percents ( % )

nuclear fission produces elements that are heavier than helium.

the elements that are used in nuclear fission and their products are much heavier than helium.