Milk is composed of water, carbohydrates, proteins, fats, and certain minerals and vitamins. The graph shows the outcome of an experiment. For 18 days, one group of young rats received $3\,\text{cm}^3$ of milk each day. On day 18, this group stopped receiving milk, whereas a second group of young rats was given milk. All other variables were kept the same for both groups of rats. What explains these results?
- AWhether or not young rats are given milk, their mass is always the same on day 46.
- BMilk contains the nutrients needed for young rats to grow.
- CMilk is not important for the growth of young rats.
- DYoung rats grow fastest after day 18.