The outer covering of a reptile egg, may be flexible, calcified eggshells, while there are some reptiles that has hard eggs. A snake lays a kind of reptile egg that is leathery. A reptile egg may differ from one another, depending on the species.
Hello Daniel......
Have a beautiful and joyful day ahead.
The hedgehog are animals with spiny armor that protects it from predators and cushions its falls from trees. Animals have different survival mechanisms and means to protect themselves from possible predators. For example; a Camel has long eyelashes and hair-lined ears that blocks blowing sand, can close its nostrils to keep sand out. Others like Koala uses specially designed hands and feet and a thick, padded tail to hold on to tree branches for long periods of time.
Population decreases by 15.
Birth rate means more population (positive), death rate means less population (negative), immigration means more (positive), and emigration means less (negative). So, just add and subtract the appropriate numbers:

Negative 15 people means that the population decreases by 15.