Vatican City is home to some of the most famous art in the world. St. Peter's Basilica, whose successive architects include Bramante, Michelangelo, Giacomo della Porta, Maderno and Bernini, is a renowned work of Renaissance architecture.
This is when the baby's brain, spinal cord, heart and other organs begin to form. The embryo is now made of three layers. The top layer â the ectoderm â will give rise to your baby's outermost layer of skin, central and peripheral nervous systems, eyes, inner ears, and many connective tissues. Your baby's heart and a primitive circulatory system will form in the middle layer of cells â the mesoderm.
The gametes (an egg and a sperm) fuse in the process of syngamy to form a 2 n zygote. The zygote divides mitotically to form a multicellular embryo ( embryogenesis), which is protected by either gametophytic tissues (such as remnants of archegonia in the nonseed land plants) or sporophytic tissues (the seed in the seed plants). An embryo,...