Number 2 because they are still developing
Atoms that are unstable undergo radioactive decay,
Elements with half life(that's how we know that it decayed),
Atoms that release energy and particles(like alpha beta and gamma particles) and,
Elements that have turned into a new element (as in radioactive decay no. of protons can decrease)
And to be precise the elements that have neutron to proton ratio of more than 1 undergo radioactive decay, since the nuclear attraction gets all weird after that.
If it has a cell wall, it most likely is not a eukaryotic, or animal, cell. Plants, bacteria, and fungi, have cell walls however.
Explanation:
blood cells are BICONCAVE DISK in shaped because they lack nucleus
