Using fertilisers can lead to algae build up in ponds and rivers.

Why is that bad?

Fertilizer van leach water into fresh water, adding extra, unwanted nitrates. This will increase algal population which can cause algal blooms. Algal blooms reduce light levels, killing aquatic plants. These dead plants, as well as dead algae, become food for bacteria which increase greatly in number.

It can affect the environment in a bad way. The marine animals won't be able to survive.

Explanation:

after receiving a stimus, the sensory receptors send(s) signals to the appropriate area of the body.  

the must be sensory neurons.  

hope its .

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