How can birds develop without a placenta

What type of cell is produced after fertilization occurs and the gametes combines ?

What do isotopes of uranium have the same number of? what do they have a different number of? a) same number of protons; different number of electrons b) same number of protons; different number of neutrons c) same number of electrons; different number of protons d) same number of neutrons; different number of protons

Which is the most likely reason the writer of the play pygmalion chose to change the character of galatea from a statue to working-class woman?