Identify arrows pointing to structures containing pi bonds.

The arrows pointing to the structures containing pi bonds can be seen in the image attached below. From the assumed example Butan-1,3-diene , there are two pi bonds.

A bond is an attractive force designated by a dash (---) that holds atoms or ions mutually in a chemical bonding.

Covalent bonds exist in  organic chemistry and they are of two types:

The sigma bond (σ) exists as a single bond that occurs by the overlapping of an s-s atomic orbital or s-p atomic orbital. They can be seen in unsaturated straight chains such as alkane.

The pi bond (π) exists as a double bond or a triple bond that occurs by the overlapping of two unhybridized p-orbitals.

Since the diagram is not given, we use Butan-1,3-diene as an example of the required structure.

From the structure which is attached in the diagram below, we can see that there are two double bonds indicating the presence of pi-bonds.

Therefore, we can conclude that from the assumed example Butan-1,3-diene, there are two pi bonds.

Learn more about covalent bonds here:

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c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

if you're asking what comes out, it's steam.