The number of solutions of the system of equations $2x + y - z = 7$, $x - 3y + 2z = 1$, and $x + 4y - 3z = 5$ is

Both corpus luteum and macula lutea are

The given graph represents $V-I$ characteristic for a semiconductor device. Which of the following statements is correct?

Approximately $70\%$ of carbon dioxide absorbed by the blood is transported to the lungs:

Two rigid boxes containing different ideal gases are placed on a table. Box $A$ contains one mole of nitrogen at temperature $T_0$,while box $B$ contains one mole of helium at temperature $\left( \frac{7}{3} \right) T_0$. The boxes are then put into thermal contact with each other,and heat flows between them until the gases reach a common final temperature (ignore the heat capacity of the boxes). The final temperature of the gases,$T_f$,in terms of $T_0$ is:

Inverted pyramid is found in