Which of the following materials is the least porous? 1. loosely packed gravel 2.sorted sand and rock 3.unsorted sand and rock 4.large pebbles and boulders

3.unsorted sand and rock

my answer, but I'm sorry if I'm wrong

thrombocytopenia, which is a deficiency in blood platelets, can cause bleeding and bruising in the dermis similar to senile purpura. other possible causes include: exposure to ultraviolet rays and aging skin are common causes of senile purpura. senile purpura may also be a sign of collagen loss in the skin and bones.

rising temperatures because when water vapor in the air is cooled, it condenses. it turns back into a liquid and attaches to dust particles in the air. these very small water droplets group together to form clouds