During spring tide, the sun, earth, and moon are in a straight line. This causes

a
a small difference between high and low tides
b
a higher chance of lunar eclipses
c
a higher chance of solar eclipses
d
a large difference between high and low tides

- measure reactants precisely. ( first choice)

- stir to the reaction take place. ( second choice)

- wait patiently until the reaction completes. ( fourth choice)

- make sure to recover as much copper as possible. ( last choice)

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