A cause and effect structure shows that one thing or event is the result of another thing or event. Words and phrases such as "therefore", "because", "consequently", and "as a result" are commonly used in this type of structure. That is what we have in the passage we are analyzing here. Let's take a look at the following lines:
Sometimes an enemy frightens the birds who scream and fly away. As a result of the noise, the birds give the crocodiles a warning of danger.
The cause-and-effect relationship is made clear here due to the use of "as a result". We are being told that the birds' scream is the cause. The effect is the crocodiles being warned of danger.
