single-celled
in single-celled organisms they perform activities such as eating and reproducing in just one cell.
Photoexcitation<span> is the photoelectrochemical process of electron excitation by photon absorption, when the energy of the photon is too low to cause photoionization. The absorption of the photon takes place in accordance with Planck's quantum theory.</span>
The question is asking to states on how i earth's early lang environment different than today's land environment and base on my research, I would say that in the past centuries or early ages, the Earth's land environment are compost of tree and plants and the air is still fresh. I hope you are satisfied with my answer and feel free too ask for more