Question

1. salmon swim upstream to the shallows when they spawn. why do they do this and what type of adaptation is it?

Explanation:

Salmon swim upstream to shallows to spawn as shallows have gravel - beds which are ideal for laying eggs and provide protection from predators. This is a behavioral adaptation as it involves a pattern of behavior related to reproduction.

Answer:

Salmon swim upstream to the shallows to spawn because shallows have suitable gravel - beds for egg - laying and offer protection from predators. It is a behavioral adaptation.