**Core Concept**
The diaphragm is a dome-shaped muscle that separates the chest cavity from the abdominal cavity, playing a crucial role in respiration. It has specific anatomical features that enable it to function effectively.

**Why the Correct Answer is Right**
The diaphragm is an essential muscle for breathing, and its anatomy is carefully designed to accommodate this function. The left side of the diaphragm is indeed pushed down by the heart, which is located in the thoracic cavity to the left of the midline. This is due to the position of the heart and the way the diaphragm is curved. The right side of the diaphragm is also influenced by the liver, which is located in the right upper quadrant of the abdomen and pushes the diaphragm upwards. However, the right side of the diaphragm is not lower than the left. In fact, the right side is at the same level as the left side, which is lower than the left side due to the position of the heart.

**Why Each Wrong Option is Incorrect**
* **Option A:** This statement is incorrect because the left side of the diaphragm is not pushed down by the heart in the sense that it is not being pushed by the heart's weight or pressure. The heart is a muscular organ that pumps blood, and its position is due to the way the thoracic cavity is structured.
* **Option B:** This statement is incorrect because the left side of the diaphragm is actually lower than the right side, not the other way around.
* **Option C:** This statement is incorrect because the right side of the diaphragm is not lower than the left side. In fact, the right side is at the same level as the left side.
* **Option D:** This statement is incorrect because hernias are more common on the right side of the diaphragm, not the left side. This is due to the way the right crus of the diaphragm is attached to the esophageal hiatus.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the diaphragm is a dome-shaped muscle that separates the chest cavity from the abdominal cavity. The left side of the diaphragm is lower than the right side due to the position of the heart, and the right side is pushed upwards by the liver.

**Correct Answer:** D. Hernia common on right because of weak origin