commodity quality refers to the appearance and packaging of agricultural products, such as______, ______, ______ and ______. A: A.form B: B.colour and lustre C: C.uniformity D: D.chemical pollution

chemical

A chemical is any aspect of a substance which is only seen by means of a chemical reaction (反应).

A chemical compound that contains two atoms of oxygen and one atom of another chemical element is called ______

以下哪个数据库属于文摘数据库____ A: American Chemical Society B: ScienceDirect C: Springer Link D: Chemical Abstracts(CA)

以下表达“科学领域”的英语词汇是_______。 A: chemical principles B: scientific fields C: natural changes D: chemical pollution

以下表达“自然变化”的英语词汇是_______。 A: toxic chemicals B: chemical industry C: chemical changes D: natural changes

A chemical _______ is any aspect of a substance which is only seen by means of a chemical reaction (反应). A: queries B: property C: obstacles D: margins

To identify a substance, chemists observe two distinct types of , physical and chemical, which are related to physical and chemical that matters undergoes.

Nuclear rockets, in contrast to their chemical