Which animal's egg is formed of only one cell? What is it's measurement?

Question

Which animal's egg is formed of only one cell? What is it's measurement?

Answer 1

all eggs of all living beings are made up of only one cell.

the biggest cell is the ostrich's egg, and the smallest egg is that of the bee humming bird. ther smallest cell is of a creature intermediate between viri and bacteria-the mycoplasma gallisepticum

Answer 2

all eggs are one cell.  

Answer 3

all eggs have 2 cells or more

the fish eggs have just one cell

Answer 4

all animals egg have one cell . the largest is of ostrich having size of 17 cm and then of hen .