Subtract the sum of3x²y-5a+4b and-9x²y-7b+4a from their difference

answer; /// i believe that the correct answer is (c); ///when the lungs expand, they fill with air from the atmosphere;

all soils contain mineral particles, organic matter, water and air the combinations determine the soil's properties – its texture, structure, porosity, chemistry and color. soil is made up of different-sized particles. sand particles tend to be the biggest.

c- dynamic stretching