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TLS Online TPP Program

#Question id: 5122

In amphibia, when epidermal (ectodermal) and mesodermal cells are brought together in a mixed aggregate, the epidermal cells move to the periphery of the aggregate, and the mesodermal cells move to the inside by the process of selective affinity. Which of the following statement describe the phenomena of selective affinity?

#Unit 5. Developmental Biology

  1. The inner surface of the ectoderm has a positive affinity for mesodermal cells and a negative affinity for the endoderm, whereas the mesoderm has positive affinities for both ectodermal and endodermal cells.

  2. The inner surface of the ectoderm has a negative affinity for mesodermal cells and a positive affinity for the endoderm, whereas the mesoderm has negative affinities for both ectodermal and endodermal cells.

  3. The inner surface of the ectoderm has a positive affinity for mesodermal cells and a positive affinity for the endoderm, whereas the mesoderm has positive affinities for both ectodermal and endodermal cells.

  4. The inner surface of the ectoderm has a negative affinity for mesodermal cells and a negative affinity for the endoderm, whereas the mesoderm has negative affinities for both ectodermal and endodermal cells

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TLS Online TPP Program

#Question id: 24461

#Unit 7. System Physiology – Animal

An 11-year-old male was having difficulty reading the graphs that his teacher was showing at the front of classroom. His teacher recommended he be seen by an ophthalmologist. Not only was he asked to look at a Snellen letter chart for visual acuity but he was also asked to identify numbers in an Ishihara chart. He responded that he merely saw a bunch of dots. Abnormal color vision is 20 times more  common in men than women because most cases are caused by an abnormal
TLS Online TPP Program

#Question id: 7312

#Unit 5. Developmental Biology

Following statements regarding to the classes of genes that regulate floral development:

A.  Floral organ identity genes directly control floral identity. The proteins encoded by these genes are transcription factors that likely control the expression of other genes whose products are involved in the formation and/or function of floral organs.

B.  Cadastral genes act as spatial regulators of the floral organ identity genes by setting boundaries for their expression.

C.   Meristem identity genes are necessary for the initial induction of the organ identity genes. These genes are the positive regulators of floral organ identity.

D.  Cadastral genes act as negative regulators of the floral organ identity genes by inhibits their expression.

E.   Meristem identity genes are the negative regulators of floral organ identity genes.

Which of the above statements are true?
TLS Online TPP Program

#Question id: 3269

#Unit 11. Evolution and Behavior

Two plant species live in the same biome but on different continents. Although the two species are not at all closely related, they may appear quite similar as a result of
TLS Online TPP Program

#Question id: 15760

#Unit 5. Developmental Biology

Why Stem cells are sometimes referred to as “undifferentiated”?
TLS Online TPP Program

#Question id: 2788

#Unit 2. Cellular Organization

DNA that is transcriptionally active