Porosity
Porosity refers to the space inside the rock that is taken up by pore space.
The answer is B mesoderm because the embrionery orgin of the kidney is in the mesoderm
I believe the biosphere is fragile, because over time all of the pollution us humans have made; If its from air pulloution, acid rain or even water pollution. the toxic acids over time have made the biosphere and the ozon layer weaker and more thin. which causes the biosphere to become weaker.
The correct answer is C) only some survive because variation exists
