Water & Nutrients. Like humans and animals, plants need both water and nutrients (food) to survive. Most all plants use water to carry moisture and nutrients back and forth between the roots and leaves. Water, as well as nutrients, is normally taken up through the roots from the soil.
Changing from puppy food to adult food depends on the size of your dog as an adult. If he is a small breed and will not exceed 30 pounds, he is mature at 10 to 12 months old. Some small breeds are mature before 10 months of age. Medium breeds are dogs that do not exceed 80 pounds at full growth.
Depending on the breed, by the time puppies are one year old, they are considered adult dogs. Some breeds of dogs take longer to mature out of their adolescent phase than others. Less than one year will be spent in cute, cuddly puppy stage, while the next ten to 15 years you will be living with the adult dog.