1. Mutualism: This is a relationship in which both species benefit from each other. For example, some plants provide food and shelter for animals, while the animals help to pollinate the plants. Another example is the relationship between cleaner fish and larger marine animals. The cleaner fish eat parasites from the larger animals, which helps to keep the larger animals healthy.
2. Commensalism: This is a relationship in which one species benefits from the other, while the other species is not affected. For example, some birds build their nests in trees, which provides them with a safe place to live. The trees do not benefit from the birds, but they are not harmed by them either.
3. Parasitism: This is a relationship in which one species benefits from the other, while the other species is harmed. For example, some tapeworms live in the intestines of humans and other animals. The tapeworms absorb nutrients from the host's food, which can lead to malnutrition and other health problems.
4. Cooperation: This is a relationship in which two or more species work together to achieve a common goal. For example, some ants work together to build colonies and gather food. The ants benefit from working together because it allows them to accomplish things that they could not accomplish on their own.
These are just a few examples of how living things help each other. There are many other ways in which species interact with each other, and these interactions can have a significant impact on the survival and success of both species.