Which of the following statements about the evolution of life histories is correct?

A) Unstable environments with unlimited resources favor r-selected populations.

B) K-selected populations are most often found in environments where density-independent factors are important regulators of population size.

C) Most populations have both r- and K-selected characteristics that vary under different environmental conditions.

D) The reproductive efforts of r-selected populations are directed at producing just a few offspring with good competitive abilities.

#Question id: 19714

#Unit 3. Fundamental Processes

#Question id: 3940

#Unit 3. Fundamental Processes

You have examined nucleoli structures from several sources listed below and find that the cell type with the largest nucleolus is the:

#Question id: 3979

#Unit 3. Fundamental Processes

“Housekeeping genes” in bacteria are commonly expressed constitutively, but not all of these genes are expressed at the same level (the same number of molecules per cell).  The primary mechanism responsible for variations in the level of constitutive enzymes from different genes is that:

#Question id: 11815

#Unit 6. System Physiology – Plant

Some given statements about  the cytokinin signalling pathway;

a)  Cytokinin receptor CRE1 probably functions as a monomer

b) Two other hybrid sensor kinases (AHK2 and AHK3) may also act as cytokinin receptors in Arabidopsis

c) Activated receptor activates their histidine kinase activity, The phosphate is transferred to an aspartate residue (D) on the fused receiver domains

d) The phosphate is then transferred to a conserved histidine present in an AHP protein that transfer the phosphate to an aspartate residue  located within the receiver domain of type-B ARRs only

e) The phosphorylation of the type-B ARR activates the output domain to induce transcription of genes encoding type-A ARRs.

f) The phosphorylated type-A ARRs feed back to negatively regulate cytokinin signaling, thus dampening cytokinin responses

Which of the following are the correct prediction about cytokinin signalling?

#Question id: 26929

#Unit 10. Ecological Principles