A group of similar organisms that can mate with each other and produce fertile offspring. *
Natural Selection
Species
Fossil
Evolution

In the following table, all the columns for the element calcium are filled out correctly. element electron structure of atom electron structure of ion net ionic charge calcium 1s22s22p63s23p64s2 1s32s22p63s23p64s1 +1 true false

How many moles of oxygen gas are produced from the decomposition of six moles of potassium

How might this scientific phenomena be explained? a paper clip floats on water.