$($no explanation necessary$)$

a$)$ The P$-$V diagram shows "point $1".$ Circle all the choices that make sense at point $1$:

i$)P_1$

ii$)V_1$

iii$)T_1$

iv$)Q_1$

v$)W_1$

b$)$ The P$-$V diagram below shows a compression at constant pressure, from point $2$ to point $3.$ During this process, $($circle one choice$)$:

i$)T=0$

ii$)T$ is positive

iii$)T$ is negative