No, the Moon is always lit by the sun.

Yes, always in Diagrams 2 and 3, but never in Diagram 1.

Yes, always in Diagram 2, but never in Diagrams 1 or 3.

Yes, always in Diagram 2 and sometimes in Diagram 3.

Because Leticia’s diagram is showing that the half of the Moon that is facing the sun is lit by the sun, and the other half is dark.

Because the Moon has some lighter-colored rock and some darker-colored rock, and Leticia’s diagram is showing that the half of the Moon with the lighter-colored rock has rotated to the left.

Because as the Moon gets closer to the sun, more of it is lit by the sun, so Leticia’s diagram is showing sunlight on half of the Moon.

Because there is a shadow from Earth falling on half of the Moon, and Leticia’s diagram is showing that shadow on the right half of the Moon.

Between the first observation and the second observation, the Moon moved so that Tania was able to see more of the half that faces the sun.

Between the first observation and the second observation, the Moon moved closer to the sun so more sunlight reached the Moon’s surface.

Between the first observation and the second observation, the Moon rotated so that more of the light-colored rock on the Moon’s surface faced Earth.

Between the first observation and the second observation, Earth moved so its shadow was blocking less of the Moon so Tania was able to see more of it.

Light travels in straight lines only.

Light travels like a river, wherever there is an open path.

Light travels in unpredictable ways.

It depends; if the light is bright enough it can change direction.

About one week.

About one month.

There is no way to tell because the Moon’s pattern is always changing.

It could be two weeks or a month, depending on what time of year it is.