题目内容

Mother solution C of nutrient solution mainly contains______()

A. iron and trace elements
B. zinc and trace elements
C. magnesium and trace elements
D. copper and trace elements

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Common solid medium of soilless cultivation include()

A. grass charcoal
B. perlite
C. rock wool
D. gravel

Depending on the fact whether the cultivation beds are applicable to solid medium materials, the soilless cultivation is divided into()and()

A. hydroponic cultivation
B. soil medium cultivation
C. non-solid medium cultivation
D. aeroponic cultivation

American scientists_showed the necessity of adding trace elements based on the results of experiments, and released the standard formula of nutrient solution accordingly()

A. Wigman and Boussingault
Boiussingault and Anon
C. Sax and Norbert
D. Hoglaland and Anon

which theories listed below are based on the pre-assumption of informationally efficient market()

A. MM theory
B. agency thory
CAPM theory
D. OPT theory

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