1. the first and shortest stage of prenatal development is where the the zygote begins to grow in complexity during the first two weeks of conception. 2. the stage lasts from 2 - 8 weeks following fertilization, when major organs and basic anatomy begin to develop. 3. the stage lasts from 8 weeks until birth and involved the differentiation of major organs.

The first and Shortest stage of prenatal development is Germinal stage, where the zygote begins to grow in complexity during first two weeks of conception.

The embryonic stage lasts from 2-8 weeks following fertilisation,when major organ and basic anatomy begin to develop.

The fetal stage lasts from 8 weeks until birth and involved the differentiation of major organs.

Explanation:

Periods of pregnacy and major events are as follows:

Implantation follows the germinal stage.Embryonic stage begins at 2 weeks and following events occur:End of one month : Embryo's heart begins to beat.End of second month: limbs become paddle like.Fetal stage begins:first trimesters: major organ systems established.End of fourth month: nerve fibre formation begins. End of fifth month: First movement of foetus,; eruption of hair.End of sixth month: Fine hairs appear on body, eyelids separate.End of eighth month: Testes descends into scrotum.End of ninth month: Foetus completely developed and ready for birth

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