Three processes that occur in cells are described in the box. • Substances pass through the lipid bilayer of a cell from areas of high concentration to areas of low
concentration.
• Substances move through protein channels of the lipid bilayer of a cell from areas of high concentration to
areas of low concentration.
• Substances move through the lipid bilayer of a cell from areas of low concentration to areas of high
concentration.
These processes are all examples of -


the earth is thought to have been formed about 4.6 billion years ago by collisions from a cloud of hydrogen, helium, rock, ice and other materials. these were pulled together by gravity to form objects in and around earth like- asteroids and small early planets called planetesimals.

so, the best possible answer to this question will be option d- to harden materials to form different parts of earth’s layers

a ratio derived from the equality between two different units that can be used to convert from one unit to the other. information obtained from experiments, sometimes called experimental results. the part of the experiment that is affected by the independent variable.