Answer:
so the third one
Explanation:
During the day, the sun heats up mountain air rapidly while the valley remains relatively cooler. Convection causes it to rise, causing a valley breeze. At night, the process is reversed. During the night the slopes get cooled and the dense air descends into the valley as the mountain wind.
Answer:
strongest oxidizing agent: 
weakest oxidizing agent: 
strongest reducing agent: Y
weakest reducing agent: X
will oxidize Z
Explanation:
The higher the reduction potential of a species, higher will be the tendency to consume electrons from another species. Hence higher will be the oxidizing power of it's oxidized form and lower will be the reducing power of it's reduced form.
Alternatively, higher reduction potential value suggests that the oxidized form of the species acts as a stronger oxidizing agent and the reduced form of the species acts as a weaker reducing agent.
Order of reduction potential:

So, strongest oxidizing agent: 
weakest oxidizing agent: 
strongest reducing agent: Y
weakest reducing agent: X
As reduction potential of the half cell
is higher than the reduction potential of the half cell
therefore
will oxidize Z into
and itself gets converted into X.
Per hour-68x60=4080
Per day-4080x24=97920
Per week-97920x7=685440
Ba2+ and Cu2+, and Sr2+ and Li+