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TLS Online TPP Program

#Question id: 7107

What would be the effect on the timing of somite formation, if a piece of the pre-somitic mesoderm of a chick embryo is rotated by 180° and reinserted in its original position?

#Unit 5. Developmental Biology
  1. there would be no effect because the embryo would regulate and development would proceed normally
  2. antero-posterior development would be blocked at that point, and more posterior structures would fail to form
  3. the rotated mesoderm will reverse the gradient of somite formation, so that somite formation posterior to the rotated mesoderm will begin in the posterior and move forward to meet the previously formed somites
  4. the timing of somite formation will be reversed in the rotated block only, proceeding from posterior to anterior, but the rest of the somites will form in a normal fashion, proceeding from anterior to posterior
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TLS Online TPP Program

#Question id: 5470

#Unit 8. Inheritance Biology

Numerous pure breeding crosses are made between two inbred plant strains, one having a mean height at maturity of 96 cm and the other as 56 cm. The height of the F1 progeny at maturity averages close to 76 cm. Height of plant control by four pair of polygene. The F2 progeny show the following phenotype.
TLS Online TPP Program

#Question id: 5471

#Unit 8. Inheritance Biology

A plant height in Maize is control by 3 pair of polygene. Two varieties of maize averaging 120 and 90 inches in height, respectively, are crossed. The F1 progeny is quite uniform averaging 105 inches in height. What will be height phenotype of F2 progenies ?
TLS Online TPP Program

#Question id: 5472

#Unit 8. Inheritance Biology

Plant height of wild Solanum nigrum is controlled by four pair of polygene. A plant genotype AaBBCcDd with 150 cm height but B plant genotype aabbccdd with 125 cm height present in their population. Following some plants with genotype AABBCCDD, AaBbCCDD, AabbccDD, aaBBccdd and their expected height in cm respectively is
TLS Online TPP Program

#Question id: 5522

#Unit 5. Developmental Biology

In reptiles, birds, and mammals, mesoderm is made by invagination and involution into the
TLS Online TPP Program

#Question id: 5523

#Unit 5. Developmental Biology

Ectodermal cells condense into placodes that change into
TLS Online TPP Program

#Question id: 5524

#Unit 5. Developmental Biology

Interaction of the optic stalk with ectoderm makes the development of the