A measurement of population per unit area
For example x amount of people in 1000 square feet
Radioisotopes tell scientists that the earth is 4.5 billion years old.
Answer:
I'm not really sure but I'll guess it's
They use C, thermal heat. This is because the vents use heat from the earth and it warms up the organisms that are very deep in the ocean. The reason they do not use sunlight is because they are so deep down in the ocean that sunlight will not reach them.
are u dumb
dont uk that poop excretes