Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to keep orphaned newborn puppies clean [title] Remove the amniotic membrane. [step] In the event of the mother dog's death or absence, she will not be able to perform several crucial actions at the time of delivery. This first of these is to remove the amniotic membrane, or the clear sac that the puppies are born in.

Ending1: After removal, the mother dog's safe place is the uterus. After the uterus has reached full capacity, the puppies are removed from the uterus, which is the inner internal sac that holds the puppies. Ending2: It is necessary to remove this immediately in order for the pups to breathe. Simply break this membrane with your fingers, and slide the puppies out. Ending3: [substeps] Opening the sac while the puppy is nursing will help provide instant warmth and nourishment to the puppy. The sac will be removed as soon as the puppy turns eighteen months old. Ending4: [substeps] Open the mother's tank and locate the amniotic membrane that you determined or suspected was lost during a previous delivery. Use a clean paperclip or some water to scrape away the membrane so that it is easy to clean.

Answer format: ending1/ending2/ending3/ending4