Answers: 1.Circulatory system-pumping blood to and from the body and lungs with the heart 2.Digestive system-digestion and processing food with salivary glands, esophagus, stomach, liver, gallbladder, pancreas, intestines, rectum, and anus.
During the tie, the male turns around so the dogs are back to back and can defend themselves. The tie typically lasts 20 to 40 minutes. It may be just a few minutes, and dogs can mate successfully without becoming tied at all. The evolutionary reason for the tie is unknown, but it's assumed that if a male dog is tied to a female, it prevents other males mating with her. Unwanted Mating.
Taut-Line Hitch. Here's how to tie a taut-line hitch--that is, two half hitches with an extra wrap. 1.Hold one end of the line in your left hand; this will be your working end. Hold the other end of the line in your right hand; this will be the standing end. Wrap the line's working end once around the tree trunk, leaving extra length.