three
Ozone (O3) is a triatomic, molecule, consisting of three oxygen atoms. Ozone in the upper atmosphere protects living organisms by preventing damaging ultraviolet light from reaching the Earth's surface. O3 is the formula for ozone. It has three oxygen atoms.
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Answer:
I think it's A " The train must be able to complete the trip in six hours "
A observation and hypothesis
Answer:
(a) Simple reflex action response to external stimuli while Condition reflex action deals with learned or modified patterns of behaviour gained through experience. (b) Simple reflex action same in all members of a species while Condition reflex action different in members of a species.
Explanation: