NOT Marie Curie :(

There's a genus of bees called Mason bees that make nests in: cracks of stones, holes in wood, or hollow stems. They also tend to nest in just about any wood they find, such as yard chairs (no source for this one just personal observation)!

The mitochondria which perform oxidative phosphorylation (a part of aerobic respiration which uses oxygen) to generate ATP! Most eukaryotic cells contain mitochondria, and for good reason, because ATP is a great source of chemical energy. The mitochondria are a big component of the endosymbiotic theory; the theory that organelles such as the mitochondria and chloroplast arose from being tiny free living prokaryotic cells that could perform aerobic respiration and photosynthesis (respectively) taken in by a eukaryotic predecessor who found their characteristics useful and decided not to eat them!

Don't they just look so weird and funky and cool?

I think it's safe to say that everybody knows about how giant pandas are at risk, but have you ever heard of the Yangtze river dolphin? No? Well, both were going extinct, but in 2006 while us regular people were donating money to save the giant panda, the Yangtze river dolphin was quietly slipping away in the wild, and was declared functionally extinct (meaning they are still found in nature reserves but not in the wild) that same year. Plants are completely out of the question in terms of cuteness conservation. Did you know that 71% of all cycads are considered threatened with extinction? 34% of conifers? Whole ecosystems could crash and burn because of our lackadaisical efforts. All this preamble to say, us humans have a problem. And our problem is that we are 100% biased towards saving what we deem cute animals, or, in conservation terms, poster species - whales, pandas, polar bears, elephants, and the like. My ecology professor brought up a great point when she said poster animals can be useful to bring in donations for broader wildlife conservation funding, but what if there's so little public knowledge about these species that they can't even attract the funding from these larger organizations? What about ugly reptiles? Amphibians? Who's going to eat all the horseflies and mosquitoes? Even then, those species eating bugs that we find annoying are still useful to us, whereas species that may be useful to their habitat at large go completely unnoticed and go extinct quietly into the night.