Fission takes place when an animal divides into two parts.
An isotope capable of undergoing fission is called a fissile isotope .
Fissile isotopes are capable of dividing into two parts.
What are capable of dividing into two parts?

a) epidermis and dermis
b) colors of the spectrum
c) rays or beams
d) bacteria
e) fissile isotopes
f) critical organs
g) objects that have mass
h) the body's largest organ