Grey spot of oat are due to
A: Copper
B: Iron
C: Manganese
D: Zinc
A: Copper
B: Iron
C: Manganese
D: Zinc
举一反三
- whichone is not trace mineral?() A: zinc B: copper C: magnesium D: iodin
- which elements belong to micro-elements？（ ） A: iron B: sodium C: zinc D: magnesium
- In addition to iron and carbon, list the other elements that may be found in a grey cast iron and describe their effect on the properties of a grey cast iron.
- The most abundant element amongst the following as found in plants is A: Carbon B: Nitrogen C: Iron D: Manganese
- What can we add to brass to improve machining: A: Tin B: Copper C: Lead D: Manganese E: Carbon nanotubes