Mangrove forest serves as a stopover for migratory birds during migration.

Coral reefs can be found in groups and form a big chain called fringing reefs.

Estuaries serves nurseries for some animals because of its less saline water compared to sea water.

The greater mass an object has the lesser in weight.

Gravity prevents things from sliding off against each other.

The nearer the objects are from each other, the bigger the gravitational pull will between them.

If you loosen your grip on the glass, friction will tighten and gravity might cause the glass to fall.

Gravity holds everything close to the planet.

Gravity increases as the distance between two objects increases.