As a person ages, his or her levels of cardiorespiratory fitness tend

tend to weaken..

Explanation:

as we age, our cardio. resp. system weaken with age. just like all the vital organs. every cell in your body lessons its a bility as u get older. cells r programmed at birth to determine the end of life..

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. will be your answer sorry if im wrong tho