When snapping shrimp are building their homes in the seafloor, goby fish keep guard and flap their tails when danger is approaching. As part of this relationship, the shrimp allow the gobies to sleep in the burrow and use it for cover from predators. This is an example of

Which statements explains what the fossil records indicates? check all that apply. a) earth is 4.5 billion years old b) many organisms have become extinct c) mammals have always existed on earth d) mass extinctions have occurred several times on earth e) the amount of water on earth has decreased over time?