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
Answer:
Lactase
Explanation:
Lac operon (lactose) is degraded to glucose and galactose by three enzymes :beta galactosidase, galactoside permease and thiogalactosidase transacetylase.
Answer:
B
Explanation:
B is the most likely consequence because of the following facts we are told:
- After apple trees were introduced, some apple maggots began feeding from and laying their eggs on apple trees
- Adult apple maggots will only mate on the type of tree on which they were born.
This provides a geographical isolation (because they are feeding and laying eggs on separate trees) and reproductive isolation (because they will only mate on the type of tree on which they are born).
These two factors increase the chances that apple maggots feeding on apple trees will only encounter those who have mated on the same tree, and continue to mate this way. Over time, the populations (i.e. apple tree vs hawthorn tree) will intermix less and less. This will mean the genetic pool will become distinct, and natural selection will be acting differently (different habitats and different genes), encouraging speciation.
Characoal has an energy more than the wood that’s why it burns hotter but if there is no sufficient air supply it will make the characoal less efficient
