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TLS Online TPP Program

#Question id: 12576

Estimates of current rates of extinction

#Unit 10. Ecological Principles
  1. Indicate that we  have reached a  state of  stable equilibrium  in  which  speciation and extinction rates are approximately equal.
  2. Suggest that one-half of all animal and plant species may be gone by the year 2100.
  3. Indicate that rates may be greater than the mass extinctions at the close of the Cretaceous period. 
  4. Indicate that only 1% of all of the species that have ever lived on Earth are still alive.
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TLS Online TPP Program

#Question id: 16953

#Unit 4. Cell Communication and Cell Signaling

The ability of any stem cell to self-renew and differentiate depends on the structural organization and cellular function of specialized anatomic microenvironments known as stem cell niches. These sequestered regions are typically populated by a supportive network of stromal cells. Stem cell niche stromal cells express soluble and membrane-bound proteins that regulate cell survival, proliferation, differentiation, and trafficking. Which statements is true about HSCs?
TLS Online TPP Program

#Question id: 16148

#Unit 4. Cell Communication and Cell Signaling

 Which statement is not true for NKT Cells?
TLS Online TPP Program

#Question id: 16147

#Unit 4. Cell Communication and Cell Signaling

 Which statement is not true for Natural killer (NK) cells?
TLS Online TPP Program

#Question id: 16146

#Unit 4. Cell Communication and Cell Signaling

If a given lymphocyte divides to form two daughter cells, both daughters bear antigen receptors with antigen specificities identical to each other and to the parental cell from which they arose, and so will any descendants they produce. The resulting population of lymphocytes, all arising from the same founding lymphocyte, is a clone. Which interleukin is responsible for clone production?
TLS Online TPP Program

#Question id: 16145

#Unit 4. Cell Communication and Cell Signaling

 Which line is not true for follicular dendritic cells?
TLS Online TPP Program

#Question id: 16144

#Unit 4. Cell Communication and Cell Signaling

  _______are motile phagocytic cells they play their most important role in the defense against multicellular parasitic organisms, including worms. They can be found clustering around invading worms, whose membranes are damaged by the activity of proteins released from its granules. it may also secrete cytokines that regulate B and T lymphocytes, thereby influencing the adaptive immune response.