Answer Happy

* 1 po Which model organism would be the best choice for studying whether 100 different teratogens affect hair development? a)mouse b)chicken c)Xenopus d)zebrafish * 1 po Why do people born with Pfeiffer Syndrome have defects in both their head and hands? They have a mutation in FGF signaling which is required for the development of the skull bones and outgrowth of the limbs. They have a mutation in RA signaling which is required for the growth in the facial prominences and in the digits. They have a defect in the same group of neural crest cells that contribute to the face and limbs. They have a defect in mesoderm migration and this tissue is needed for head and limb development.