The correct answer is "<span>a layer of smooth </span><span>muscle".
</span>In an individual's mouth, gut, and the small intestine, the mucosa, which holds tiny glands, which secrete juices in order to assist in digesting food<span>. The </span>digestive<span> tract also holds a layer of smooth </span>muscle, which <span>aids in breaking down </span>food<span> and move it along the digestive tract.</span>
The diaphragm in the diagram below is a muscle that contracts during inhalation. thus option A is correct option.
<h3>What is the role of the diaphragm?</h3>
The diaphragm, located below the lungs, is the major muscle of respiration. It is a large, dome-shaped muscle that contracts rhythmically and continually, and most of the time, involuntarily.
Upon inhalation, the diaphragm contracts and flattens and the chest cavity enlarges.
Learn more about the diaphragm here:
brainly.com/question/12920059
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Acid rain can be very harmful, mildly harmful, or not harmful at all. It mainly depends on the density of the rain, and how bad the current air pollution in the area is. Also, it depends on how often the area gets acid rain. The first few times an area gets acid rain, it's nearly harmless. Then, the next few it can be very dangerous, but eventually gets weaker over time. More air polluted areas are more likely to get much more harmful acid rain.
Summary: Acid rain is usually mildly harmful, mostly only harmful to infrastructures.<span />
