a)the number of species on Earth or b)the number of individual organisms on Earth
Answer: Human survival on Mars would require living in artificial Mars habitats with complex life-support systems. One key aspect of this would be water processing systems. Being made mainly of water, a human being would die in a matter of days without it.
Explanation: have a good day
Groundwater is the water found underground in the cracks and spaces in soil, sand, & rock.