Use symbols to distinguish between parasitism, mutualism and commensalism.

1. Parasitism (+/-)

2. Mutualism (+/+)

3. Commensalism (+/0)

Explanation:

In biology, symbols are often used to differentiate between different types of symbiosis - a certain relationship between organisms, which could be beneficial, harmful, or neutral.

To distinguish between parasitism, mutualism, and commensalism, biologists use the positive (+), negative (-), or neutral (0) symbols.

  1. Parasitism  (+/-)

One organism benefits from the other and the other one gets harmed. For example, the Gordian worm infects a cricket. It gets nutrients from the cricket and once it is fully grown and able to reproduce, it leaves the cricket's body. The cricket eventually dies. This indicates that the cricket doesn't receive any benefit, but the opposite.

+ gains (parasite); - loses (host)

  2. Mutualism (+/+)

Both organisms benefit each other. For example, the algae and the coral. The corals provide protection and refuge, plus nutrients the algae need for photosynthesis and, in turn, the algae provides oxygen.

+ gains (coral); + gains (algae)

  3. Commensalism (+/0)

In this relationship, one organism benefits the other while the other  neither benefits nor is harmed. For example, the leopard shark and remoras. Remoras attach to sharks with the aim of travelling to further areas without spending energy and the leopard shark doesn't get harmed nor is benefited by the remoras.

+ gains (remoras); 0 not benefited, not harmed (leopard shark)

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.