What is the process by which a solid changes to a liquid?

The correct answer would be melting.

Melting is a physical process by which a solid state of a substance is converted into its liquid state.

It is usually achieved by applying heat or pressure to the substance.

It helps in reaching the melting point (the minimum temperature at which solid converts into its liquid state) of the substance.

For example, ice melts at 0° C.

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.

multiply it by 5 in order for you to understand i cant give an exact answer.