Effects of grasses of vetiveria and pennisetum on trophic groups of soil nematodes
香根草属与狼尾草属植物对土壤线虫营养类群的影响?
How each trophic level obtains energy .
每一食性层如何获得能量。
However , continuous administration of trophic factors into the central nervous system is costly and difficult to maintain .
然而，连续给予中枢神经滋养因子是太过昂贵和持续上有困难。
The biosphere is a global ecosystem that can be broken down into regional or local ecosystems , or biomes . Organisms in the biosphere are classified into trophic levels and communities .
