Answer:
parasympathetic nervous system
Differentiation in plants refers to the processes by which distinct cell types arise from precursor cells and become different from each other. Plants have about a dozen basic cell types that are required for everyday functioning and survival. Additional cell types are required for sexual reproduction. While the basic diversity of plant cell types is low compared to animals, these cells are strikingly different. For example, some cells such as parenchyma cells retain the potential to respond to environmental and/or hormonal signals throughout their life and, under the right conditions, can be transformed into another cell type (transdifferentiation). Other cells such as the water-conducting vessel elements undergo cell death as part of their differentiation pathway and thus can never transdifferentiate to another cell type
Read more: http://www.biologyreference.com/Co-Dn/Differentiation-in-Plants.html#ixzz54pAhWVdn
C. Cells
Cells make up organs, which make up organisms, which make up populations
The temperature is lowest at the crust. As you get lower into the Earth's surface, the temperature gets hotter.
250 billion ± 150 billion
