In one sentence, describe what the following article is about: It's normal for puppies to bite as they develop and grow. Usually, they learn about not biting from other members of their pack, including adult dogs. Puppies learn by playing with other pack mates about when to avoid causing serious damaging through biting. If puppies don't learn to control or stop biting, the other dogs will punish the puppy more severely, possibly by biting the puppy to cause injury. If the puppy does learn easily from his pack mates, they'll become more forceful and clear about biting behavior until the puppy behaves in a manner acceptable to other members of its pack. If you allow puppy biting, it may get out of control and your puppy will not learn to control his bite. This can lead to serious behavioral issues when your puppy reaches adulthood. If you suspect your puppy is biting out of fear or anger, talk with an animal behavioral therapist, who may be able to help. It is not acceptable for puppies to bite people, or other animals, unless they are in true physical danger and need to defend themselves. If you're starting a training program with the help of a qualified trainer, consider muzzling your puppy with a basket muzzle. Your puppy will quickly learn to stop nipping or biting with the help of the muzzle, but muzzling is not recommended if you don't have a clear understanding of the training approach and goals. If the muzzle isn't introduced and used properly, your puppy can actually become more dangerous to people, especially those trying to put the muzzle on the puppy.  Rewarding the puppy by giving it a treat after wearing the muzzle can help the dog associate the muzzle with something good. This makes it less likely to be wary of you or aggressive, and it makes the whole process easier for both you and the dog. Never leave children unattended and unsupervised with dogs, even ones that seem “safe”. You may need to isolate the dog and/or crate him when a knowledgeable adult cannot be present.
Summary: Understand how puppies usually learn about biting. Realize the importance of teaching your dog not to bite. Take safety precautions if your puppy bites.

Problem: Article: How we feel inside is expressed in our eyes and on our faces. Learning to recognize the association between facial expressions and certain types of emotion goes a long way in being able to read emotion. Don’t be fooled! People can manipulate their facial expressions to appear to look happy when they are angry or sad – actors do this convincingly all the time. Look for other cues as to how they really feel. Note her body language or tone of voice. Make eye contact – open, penetrating “cold” eyes suggests a different emotional state than a “warm” smile. A genuine smile uses more muscles than one that is faked or forced. The corners of her mouth and cheeks should be raised. If the muscles around her eyes also tighten and “crow’s feet” form (clusters of wrinkles around the outer corners of eyes), then it is a good indicator of a genuine smile. This might seem obvious, but people try to control or cover-up their true emotions by smiling when they are sad. Genuine and spontaneous emotions are hard to fake. Sadness is associated with frowning (lowering the corners of the mouth). It is also associated with raising the inner corners of the eyebrows (near the noise). Additional cues are loose, drooping eyelids that cover part of the eye. Anger and disgust are often associated with one another and create similar facial expressions. We wrinkle our noses when we are disgusted, angry, or annoyed.  Anger and resentment can be towards someone or about something. When we are angry, we pull our eyebrows down, purse our lips (tighten them and suck-in the margins), and bulge our eyes. In contrast to anger, expressing dislike, disgust, or disdain for someone or something is associated with a raised upper lip and loose lower lip. We also pull our eyebrows down, but not as much as when we are angry. While fear is a negative and surprise is considered a positive emotion, both activate the sympathetic nervous system and trigger a “fight or flight” response. When something unexpected happens, whether it is good or bad, it stimulates a part of the brain that is outside of our direct control. When this happens, we pull up our eyebrows and eyelids so our eyes are wide open.  When we are afraid, we also pull our eyebrows in (towards the nose), our pupils dilate (get bigger) to take in more light, and our mouth is open. We also tense up the muscles in our face, especially around our mouth and cheek. When we are surprised, we tend to arch our eyebrows and drop our jaw. Our mouth is open, and the muscles around it are relaxed and loose.
Summary:
Take note of her facial expressions. Recognize a genuine smile. Distinguish sadness from happiness. Recognize anger and disgust. Recognize fear and surprise.