Quiz Teens age 13-15

Coral is a cavity animal and consists of sea creatures of only a few millimeters which, with their tentacles, resemble a sea anemone. These animals, also called polyps, often live in colonies. There are 4,500 species. How much can you discover in our aquariums?

The pufferfish is very toxic due to the presence of the substance 'tetrodotoxin', which has a paralyzing effect. For this reason, the trade and serving of this fish in the Netherlands is prohibited by law. The fish dish is very popular in Japan. The eating of 'fugu' is seen as a status symbol. The fish itself seems to be a real delicacy.

The tail fin is missing on the sea horses. They have no scales, but rows of bumps or spikes: called leg rings. As a result, a sea horse has both an internal and external skeleton and is too tough for many animals to eat. A sea horse swims upright and moves slowly. The spine is used for propulsion. The chest fins, which are placed very high just behind the gusset covers, are used to steer. His two eyes can move independently, so that the entire body does not have to be rotated to follow something.

Harbor Seals or seals (Phocidae) form a family of marine mammals. They belong to the predators (Carnivora). Seals in the Netherlands are most common in the Wadden Sea, furthermore in the Ooster- and Westerschelde.

An octopus has 3 hearts: 1 for pumping blood through the body and 2 hearts to pump the blood through the gills.

There are over 32,000 known species, divided into more than 500 families. A new species is detected almost daily.

Many rivers flow in the North sea carrying rich water. As a result, algae can live in the North Sea. These algae have a green color. In many other seas (including the Mediterranean), less rich water comes from the rivers. Thus, in these seas, there is little algae, which makes the sea water colour blue.

A water molecule is a chemical compound of two hydrogen atoms and an oxygen atom. The molecular formula is H 2 O.

About 70% of our earth is covered with water. The seas and oceans take much of it. More than 94% of all water is in it. 4.2% of the water is in ground. Glaciers in the mountains contain 1.6% of all water. Surface water accounts for only 0.23% and 0.014% in the atmosphere contains water vapor.

The seawater temperatures are measured with an instrument aboard a satellite flying at more than 800 kms height.