Sedimentary rocks are
a. generally less porous than igneous rocks
b. less likely to serve as aquifers than igneous rocks are
c. equally as porous as igneous rocks
d. generally more porous than igneous rocks

The correct answer is - d. generally more porous than igneous rocks.

The porosity represents the percentage of void space in rocks. Porosity is the ratio of the volume of the voids or pore space divided by the total volume. Sedimentary rocks and igneous rocks are on the opposite ends on the porosity scale, the sedimentary rocks are the most porous rocks, while the igneous are the least porous rocks. This is due to the structure of the rocks, while the sedimentary are the ones with the least strong structure, the igneous are the ones with the strongest structure.

the value of the 4 in the hundreds place is 400 while the value of th e 4 in the tens place is 40

400 is way bigger than 40.