Question

read the text.
each piece of popping corn is called a kernel. inside each kernel is a hard shell called a hull, and inside each hull is a drop of water. when popcorn is heated, the drop of water in the hull turns to steam. pressure begins to build inside the kernel. eventually, the kernel explodes due to the increased pressure, and it becomes popcorn.
match causes with their effects.
pressure builds. popcorn gets hot.
cause effect
the water drop becomes steam.
the kernel pops.

Explanation:

According to the text, when popcorn is heated (Popcorn gets hot - cause), the drop of water in the hull turns to steam (effect). When pressure builds (cause), the kernel pops (effect).

Answer:

Cause: Popcorn gets hot. Effect: The water drop becomes steam.
Cause: Pressure builds. Effect: The kernel pops.