Cassie is writing an equation to show the effect of gravitational pull of the sun and moon on tidal range which equation would Cassie use to show the effect of the sun and the moon on Spring tides?

A - sun + moon = spring tides

B - sun + Earth = spring tides

C - moon - sun = spring tides

D - earth - moon = spring tides

To determine which equation Cassie would use to show the effect of the sun and the moon on Spring tides, we need to understand the relationship between the sun, moon, and Earth in causing these tides.

Spring tides occur when the gravitational forces of the sun and moon align and combine, resulting in higher tidal ranges. This happens during both the new moon and full moon phases.

Given this information, we can now evaluate each equation:

A - sun + moon = spring tides: This equation correctly acknowledges both the sun and moon, but it doesn't reflect their combined gravitational effect. The "+" operator implies that the forces are being added together but doesn't specify if they are aligned or not, making this equation incorrect.

B - sun + Earth = spring tides: This equation includes the sun and Earth, but it doesn't account for the moon's gravitational effect. As a result, it's not an accurate representation of the cause of spring tides, making this equation incorrect.

C - moon - sun = spring tides: This equation subtracts the sun's gravitational effect from the moon's. While the moon does have the stronger influence on tides, subtracting the sun's effect is not a correct representation of the alignment required for spring tides. Therefore, this equation is also incorrect.

D - earth - moon = spring tides: This equation subtracts the moon's gravitational effect from Earth. Again, this equation doesn't accurately represent the alignment of gravitational forces required for spring tides, so it is incorrect as well.

Based on our evaluation, none of the provided equations accurately represent the effect of the sun and moon on Spring tides.

Cassie would use equation A to show the effect of the sun and the moon on spring tides.