The stress vs. strain curve for the elastic tissue of the aorta,the large tube (vessel) carrying blood from the heart,will be: [Note: Stress is proportional to the square of the strain for the elastic tissue of the aorta.]

The strain-stress curves of three wires of different materials are shown in the figure. $P, Q$ and $R$ are the elastic limits of the wires. The figure shows that

The potential energy $U$ between two molecules as a function of the distance $X$ between them is shown in the figure. The two molecules are

The stress-strain curves are drawn for two different materials $X$ and $Y$. It is observed that the ultimate strength point and the fracture point are close to each other for material $X$ but are far apart for material $Y$. We can say that materials $X$ and $Y$ are likely to be (respectively)

In the given stress-strain graph,what does point $D$ indicate?

The figure shows the graph between stress and strain for a uniform wire at two different temperatures. Then: