Which of the following embryonic materials is matched with a correct post-natal (after birth) derivative? (Chose the most correc
t answer.) a. Mesoderm, skin
b. Neural crest peripheral nervous system
c. Endoderm, kidneys+ gonads
d. Ectoderm, most, but not all of skeleton
e. Mesoderm, skeleton
Neural crest are bilateral paired cells of the neural tube that arise from the ectoderm layer of the embryo. Thesescells move to different part of the body and differentiate into various cell types like melanocytes,cartilage and bone, smooth muscle, craniofacial, neurons, gangalia e.t.c. The neural crest running through neural tube develop into peripheral nervous system after birth. Peripheral nervous system consist of neurons and gangalia outside the nervous system The peripheral nervous system connect the central nervous system to organs, skin and limbs.
Operons afford the organism the opportunity to
simultaneously regulate transcription of multiple genes, whose products are
active in the same process. Operons lead to the synthesis of groups of functionally
related enzymes, usually from a single mRNA transcript hence makes regulation of
the genes highly efficient.
Fruits and vegetables have changed a lot since the onset of agriculture 10,000 years ago, as generation after generation of farmers artificially bred crops to select for more desirable traits like size and taste.
