What is the most important and effective action to take in resuscitation?

The most important and effective action to take in resuscitation is to start chest compressions immediately.

By doing this, you can help to circulate blood and oxygen to the person's brain and other vital organs. This can help to improve their chances of survival.

Here are the steps on how to perform chest compressions:

1. Place the person on their back on a firm surface.

2. Kneel beside the person's chest.

3. Place the heel of one hand on the person's sternum, between their nipples.

4. Place your other hand over the first hand, interlocking your fingers.

5. Use your body weight to press down on the person's chest.

6. Press down 30 times at a rate of 100 to 120 compressions per minute.

7. Allow the person's chest to recoil completely after each compression.

Continue chest compressions until help arrives.

Starting CPR as quickly as possible can make a big difference in the person's chances of survival.