21. Radioactive isotopes can continue to release energy over periods ranging from weeks to decades. 22. Plants use these organic compounds to build structural components or respire them to release energy . 23. To operate they constantly take in and release energy . 24. Fusion relies on the merging of nature's lightest elements to release energy , including radioactive byproducts. 25. They undergo electrochemical reactions to store or release energy . 26. If breaking bonds released energy , they would break spontaneously and molecules would not be stable. 27. In the atmosphere it condenses again, releasing energy that fuels updrafts, and thereby forms clouds. 28. Burning iron does not release energy ; it absorbs energy. 29. The positrons will almost instantly annihilate with electrons, releasing energy in the form of gamma rays. 30. Like us, many bacteria must respire _ combine food with some other substance to release energy .
