Answer: Space.
Step-by-step explanation:
Five essential requirements that maintain a viable habitat are:
- Food
- Water
- Cover: Cover provides shelter from the predators, so that the animals can safely feed, breed, nest, travel, etc.
- Space: There must be enough space to avoid competition for food. Moreover, the environment should not be over-crowded, as it leads to various diseases.
- Arrangement: The better the arrangement of food, water, cover and space is, the easier it is for animals to satisfy all their needs in a small area.