Although, I'm not sure about the entirety of this question, when reviewing claims and evidence, check your sources to make sure they are reliable.
If I recall correctly, I was taught:
The particles in the air (dust, smoke, etc.) increase in density the farther you look. Causing a "fog" effect as you look across large distances. Including shore to shore of an ocean.
The tissue in the wall of the uterus that is required for labor contractions are SMOOTH MUSCLES. Smooth muscles, also known as involuntary muscles are found in walls of hollow organs such as the stomach, gullet, bronchi, etc. Smooth muscles principally function as stimulator for movement. Examples of smooth muscles in the human body include:
1.Uterus smooth muscles: enhancing pushing during birth labour
2. Bladder smooth muscle: helps push out urine.
3. Smooth muscles also help the flow of blood in the blood vessels and the flow of food through the digestive system.<span />
