Some experts point out that "there is always some uncertainty in scientific conclusions, and science can never prove anything absolutely. When someone says that society should wait until scientists can be absolutely certain before taking action, this is equivalent to saying that society should never take action "For issues like climate change that can cause major disasters, inaction is our planet's adventure. ". Based on this, which of the following assertions must be agreed by the above experts? ['If we act, we will not let our planet risk.', 'Only by taking action will our planet not be risked.', 'Society should take action only after scientists are fully convinced.', 'Society should not act if scientists cannot be absolutely sure of anything.']