Complex sentence: It has since been supplanted in such roles by the earth-penetrating B61 Mod 11, a bomb that penetrates the surface delivers much more of its explosive energy into the ground and therefore needs a much smaller yield to produce the same effects.
Split into simpler sentences: It has since been supplanted in such roles by the earth-penetrating B61 Mod 11. A bomb that penetrates the surface delivers much more of its explosive energy into the ground and therefore needs a much smaller yield to produce the same effects.