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TLS Online TPP Program

#Question id: 13020

Experts in deer ecology generally agree that population sizes of deer that live in temperate climates are limited by winter snow. The deer congregate in ?yarding? areas under evergreen trees because venturing out to feed in winter is energetically too expensive when snowfall depths accumulate to above 40 cm. Deer often stay yarded until the spring thaw. Snow depth over 40 inches for more than 60 days results in high mortality due to starvation.  This observation best illustrates which of the following principles about factors that limit distribution of organisms?

#Unit 10. Ecological Principles
  1. Abiotic factors, such as weather extremes, ultimately limit distribution.
  2. Organisms will face extinction unless they adapt to conditions or evolve new mechanisms for survival. 
  3. Environmental factors are limiting not only in amount but also in longevity.
  4. Daily accumulations in snow depth gradually add up to cause increased deer mortality
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TLS Online TPP Program

#Question id: 15335

#Unit 4. Cell Communication and Cell Signaling

Some given following co-receptor present on to the B-cell surface except
TLS Online TPP Program

#Question id: 15336

#Unit 4. Cell Communication and Cell Signaling

Which of the following cell surface markers responsible for the regulation of B-cell ?
TLS Online TPP Program

#Question id: 15337

#Unit 4. Cell Communication and Cell Signaling

HSCs express which type of cell-surface molecule, which is the receptor for stem cell factor (SCF). It is a cytokine that exists in both membrane-bound and soluble forms and the SCF-surface molecules interaction is critical for the development, in adult animals, of multipotential progenitor cells (MPPs).  Which type of surface molecules HSCs express?
TLS Online TPP Program

#Question id: 15338

#Unit 4. Cell Communication and Cell Signaling

Which cell generated on the receipt of SCF/c-Kit signaling lose the capacity for extensive self-renewal, but retain the potential to differentiate into several different hematopoietic lineages and also transiently express the molecule CD34?
TLS Online TPP Program

#Question id: 15339

#Unit 4. Cell Communication and Cell Signaling

HSCs begin their life in close contact with osteoblasts located close to the lining of the endosteal cavity. Once differentiated to the pre-pro-B-cell stage, the developing B cells require Which type of signals from the chemokine, which is secreted by a specialized set of stromal cells?
TLS Online TPP Program

#Question id: 15340

#Unit 4. Cell Communication and Cell Signaling

Serrogate light chain formation takes place in