a) waterproofing the surface layer
Endodermos
b) rapidly dividing into new cells
Mitosis
c) transporting sugars throughout the plant
Phloem
40)Maple syrup is produces from the sap moving in the xylem of maple trees in the early spring. How would taking too much sap in the spring harm the maple tree?
That sap is an energy store to give it a strong start in spring. If you take too much, that is less energy for the tree to use.
41) A number of plants are currently being stydies for use in cleaning up land sites contanining toxic substances.
a)name the technique of using plants for this purpose
Phytoremediation
b)describe one way plants can clean up toxic substances
Phytoextraction (or phytoaccumulation) uses plants or algae to remove contaminants from soils, sediments or water into harvestable plant biomass (organisms that take larger-than-normal amounts of contaminants from the soil are called hyperaccumulators). Phytoextraction has been growing rapidly in popularity worldwide for the last twenty years or so. In general, this process has been tried more often for extracting heavy metals than for organics. At the time of disposal, contaminants are typically concentrated in the much smaller volume of the plant matter than in the initially contaminated soil or sediment. 'Mining with plants', or phytomining, is also being experimented with. The plants absorb contaminants through the root system and store them in the root biomass and/or transport them up into the stems and/or leaves. A living plant may continue to absorb contaminants until it is harvested. After harvest, a lower level of the contaminant will remain in the soil, so the growth/harvest cycle must usually be repeated through several crops to achieve a significant cleanup. After the process, the cleaned soil can support other vegetation.
c) list two advantages and two