What effect did an isolated environment have on marsupials? * It made the koala become the most famous and popular marsupial.
Marsupials spread all over the world so that they could survive.
There are now many different species of marsupials in Oceania.
It caused meat-eating marsupials to become extinct.

the correct answer is c   with the systems

it's diluted or concentrated

in a diluted solution, you can add a lot more solute but in concentrated only a little more can be added

these muscles maintain the blood pressure in the vessels. the smooth muscles are innervated by nerves of the autonomic nervous system. when the muscles contract, they cause vasoconstriction of the vessels and increase blood pressure. when the muscles relax, they enable vasodilation of the   blood vessels hence reduce blood pressure.