Which characteristic is common of cnidarians A- They live only in the oceans
B- They have four legs
C- They live at the surface of the water
D- They have tentacles

If a hydrogen atom is neutral, it must also have  one electron. an oxygen atom (o) has an atomic number of eight (8). this means a neutral oxygen atom has eight protons and eight electrons. the element actium (ac) has an atomic number of 89, so it has 89 protons and 89 electrons in a neutral atom

Ireally don’t know this