At the start of what 2 seasons do all areas of the earth get 12 hours of a day and 12 hours of night

Ruby is conducting an investigation. an advantage of her design is that she can use a large range of variables, with that she can not be sure that one variable is the cause of another. what kind of investigation is ruby most likely conducting?

What will happen to the amount of food available as a pondwater ecosystem ages

Ducks and beavers both have webbed feet