I believe that the correct answer is D.
Answer:
Muscle contraction is the activation of tension-generating sites within muscle fibers. In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle length, such as by holding a heavy book or a dumbbell at the same position. The termination of muscle contraction is followed by muscle relaxation, which is a return of the muscle fibers to their low tension-generating state.
Explanation:
Answer: The digestive tract starts by chewing and swallowing food. From there the food travels down the esophagus easily because it goes with a liquid Siliva enzyme. After, the food goes into the stomach where it is processed into a thick liquid called chyme. It then travels to the lower part of the stomach known as the atrium where it is ready to be released into the small intestine. The small intestine, or small bowel, is a hollow tube about 20 feet long that runs from the stomach to the beginning of the large intestine. The small intestine breaks down food from the stomach and absorbs much of the nutrients from the food. The food then travels to the large intestine where salts and sugars that could not be digested are absorbed. The rectum stores the stool, then the anus pushes it out in a bowl movement.
Explanation:
I wrote it all myself.
The correct answer
Physical activity ensures that the body burns all the excess calories. Excess calories is normally converted into fat that is stored in the body causing obesity and heart diseases because some of these fats are stored in the blood vessels thus hindering blood circulation. This means that in such event where tats deposit in the blood vessels conditions such as heart ischemia arises therefere, lowering the health of the victim. in summary, physical activities increases wellness and fitness while lack of physical activity reduces one health.
