An ectotherm is an animal that relies on environmental interactions to control its body temperature. which of the following animals is an ectotherm?
a) robin
b) koala
c) horse
d) anaconda

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