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

Ascience research group is testing a new type of plant food. one trial is conducted in a controlled experiment. the data from the trial show that the plant that received the new food grew faster than the control plant. the group announces that the new plant food makes plants grow faster. what is the main weakness in this scientific claim?

Which could be a pathway of food through an ecosystem

Cells must be in osmotic equilibrium with their surroundings environments because if they swell or shrink thier membranes will rupture