\begin{tabular}{l} 2.7 Plant-like Protisia. \\ The mutualistic relationship between a fungus and an alga. \\ 2.9 Organisms that have a definite nucleus. \\ \hline\end{tabular}

Did you know that the partnership between fungi and algae forms lichens, which are incredibly resilient organisms? Found in some of the harshest environments on Earth, lichens can survive extreme temperatures and radiation levels. They also contribute to soil formation and ecosystem health by breaking down rocks and providing habitats for other species. Pretty cool, right? In addition to being ecological superheroes, lichens have been used by humans for various purposes throughout history! From being natural dyes to indicators of air quality, their presence or absence can tell us a lot about the environment. So next time you spot a funky, colorful patch on a tree or rock, remember you’re looking at a remarkable collaboration that has thrived for centuries!