Crayfish are invertebrates which means they don't have a backbone. They are also arthropods, which means that they have a protective exoskeleton on the outside of their body. Other arthropods include insects, spiders, and centipedes. Crayfish continually shed their exoskeleton and regrow a new one. During this transition is when they are most vulnerable to predators because they aren't protected by their outer shell.
Crayfish are found all over the world in many different freshwater environments, such as rivers, creeks, springs, and swamps. But this doesn't necessarily mean that you will be able to find them. They are somewhat cryptic because they dig out homes for themselves under rocks and blend in well with their environment. Crayfish will ardently defend this dwelling against intruders using their strong front claws
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I believe you can prove a theory more than a hypothesis. A law is definite.
Question number 2 the dna the answer is number 4 the last one
Because predators and prey must learn (or adapt) new ways of survival. Deer over time have learned to be much more sensitive to the surrounding environment, therefore, a deer's predator must also adapt/evolve and learn how to beat the deer at it's own game and catch it for food. Animals must evolve/adapt to any given environment. If humans lived in Antarctica for thousands of years, we would eventually be able to withstand the cold due to evolution. People who live in the Himalayas today actually breath normally at such high altitudes whereas if someone who lives at sea level went to where the Himalayan people lived, the result could potentiality be fatal because the body has not adapted/evolved at that point to withstand minimal oxygen.
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The passing of genetic information from one generation to the next
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