Unless is similar in meaning to if not and can be used instead of if not in certain types of conditional sentences. You won't get in to see the show, if you don't have reserved seats. Unless you have reserved seats, you won't get in to see the show.
Best Answer: Internal fertilization is when the sperm is directly deposited into the female, who produces eggs and fertilizes them in her body.External fertilization is when the sperm and eggs are released outside of the body and meet outside of the body, not like how chithra described.Birds do not have external fertilization, the fertilization still occurs in the body, they just do not produce live young.xternal fertilization is when the sperm and eggs are released outside of the body and meet outside of the body, not like how chithra described. Birds do not have external fertilization, the fertilization still occurs in the body, they just do not produce live young.
Implantation is the process whereby the early embryo embeds into the inner wall of the motherâs uterus. Implantation begins about 6 days after fertilization and is complete by about 12 days.The first step of this process is the attachment phase, which begins about 6 days after fertilization [Fig rr].s the 2 sets of chromosomes migrate to opposite ends of the zygote, a crease begins to form along the equator marking the impending line of division. (Fig xx) The zygote or single-cell embryo completes the first cell division approximately 24 to 30 hours after fertilization.