Which sequence correctly orders early mammalian development after fertilization?

• A. Zygote followed by cleavage then implantation before blastocyst formation
• B. Zygote followed by morula then blastocyst before implantation
• C. Zygote followed by blastocyst then morula before implantation
• D. Zygote followed by gastrula then morula before implantation

Answer: (B)