What was one direct cause of the crusades?

The diagram shows the positions of the sun, moon and earth during spring tides, when the high tides are at their highest and low tides at their lowest. what is it about these positions that causes these high and low tides?

What is the approximate circumference of the circle shown below? 12.2 cm

Ateam of researchers calculates that a glacier will melt completely away in the next 100 years. which land structure will most likely be left behind after the glacier melts?