Provide your best answer for the following question. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The question is: An elephant is a multicellular organism that weighs about 200 pounds at birth and can grow to weigh as much as 15,000 pounds. What increases as the elephant grows into an adult?
the number of cells in its body
The weight.