【单选题】A(n) _____ is a small piece of software that acts on your behalf (on behalf of another piece of software) performing tasks assigned to it.
A.
agent-based technology
【简答题】大气中的硫和氮的氧化物有____和____两个来源。二氧化硫的自然来源包括____和____,含盐的海水飞沫也增加大气中的硫。
【单选题】A(n) _ is a very small piece of matter with a negative electrical charge, found in all atoms.
【单选题】Even in small colleges, computers are a(n) ___ piece of equipment.
【多选题】具有封口功能的装置设备,主要装置有哪些?
【多选题】养殖水环境中氧气的可能来源包括( )
A.
生物供氧:产氧光合生物(藻草)在光照下经光合作用产氧。
B.
物理供氧:把空气或氧气,经水气混合,溶入水。
C.
化学供氧:水中投入化学物质,发生化学反应释放出氧。