#Question id: 7194
#Unit 5. Developmental Biology
Formation
of digits and sculpting the tetrapod limb requires death of specific cells in
the limb in a programmed manner. Which one of the following interactions could
explain proper limb formation?
#Question id: 12518
#Unit 6. System Physiology – Plant
#Question id: 8680
#Unit 9. Diversity of Life Forms
Giardia intestinalis can cause disease in several different mammalian species, including humans. Giardia organisms (G. intestinalis) that infect humans are similar morphologically to those that infect other mammals, thus they have been considered a single species. However, G. intestinalis has been divided into different subgroups based on their host and a few other characteristics. In 1999, a DNA sequence comparison study tested the hypothesis that these subgroups actually constitute different species. The following phylogenetic tree was constructed from the sequence comparison of rRNA from several subgroups of G. intestinalis and a few other morphologically distinct species of Giardia. The researchers concluded that the subgroups of Giardia are sufficiently different from one another genetically that they could be considered different species
By examining the phylogenetic tree diagrammed in the figure above, what conclusion can you draw about the species G. microti?
#Question id: 14883
#Unit 4. Cell Communication and Cell Signaling
#Question id: 11720
#Unit 6. System Physiology – Plant
The embryo, which will grow into the new seedling, has a specialized absorptive organ that is___