![Which is the smallest living organism that has a brain and the biggest living organism that doesn't have a brain? | Homework.Study.com Which is the smallest living organism that has a brain and the biggest living organism that doesn't have a brain? | Homework.Study.com](https://homework.study.com/cimages/videopreview/videopreview-full/invertebrates-organ-systems-and-reproduction1_181006.jpg)
Which is the smallest living organism that has a brain and the biggest living organism that doesn't have a brain? | Homework.Study.com
![WWF on X: "Meet the tardigrade, nature's smallest animal. At first glance, they can seem creepy but they are actually amazing! From microorganisms like this to worms, ants and moles, our soil WWF on X: "Meet the tardigrade, nature's smallest animal. At first glance, they can seem creepy but they are actually amazing! From microorganisms like this to worms, ants and moles, our soil](https://pbs.twimg.com/media/EodVj13XYAAzWTp.jpg)
WWF on X: "Meet the tardigrade, nature's smallest animal. At first glance, they can seem creepy but they are actually amazing! From microorganisms like this to worms, ants and moles, our soil
![This tiny animal can survive basically anything, including the vacuum of space - The Washington Post This tiny animal can survive basically anything, including the vacuum of space - The Washington Post](http://www.washingtonpost.com/news/speaking-of-science/wp-content/uploads/sites/36/2015/04/11b.-Tardigrade_SciSource_BS9660_final-725x1024.jpg)
This tiny animal can survive basically anything, including the vacuum of space - The Washington Post
![This tiny animal can survive basically anything, including the vacuum of space - The Washington Post This tiny animal can survive basically anything, including the vacuum of space - The Washington Post](http://www.washingtonpost.com/news/speaking-of-science/wp-content/uploads/sites/36/2015/04/11b.-Tardigrade_SciSource_BS9660_final2.jpg)
This tiny animal can survive basically anything, including the vacuum of space - The Washington Post
![Mycoplasma bacteria, computer illustration. Mycoplasmas are the smallest cellular organisms known (diameter 0.3-0.9 microns). They resemble bacteria i Stock Photo - Alamy Mycoplasma bacteria, computer illustration. Mycoplasmas are the smallest cellular organisms known (diameter 0.3-0.9 microns). They resemble bacteria i Stock Photo - Alamy](https://l450v.alamy.com/450v/2r728ha/mycoplasma-bacteria-computer-illustration-mycoplasmas-are-the-smallest-cellular-organisms-known-diameter-03-09-microns-they-resemble-bacteria-i-2r728ha.jpg)
Mycoplasma bacteria, computer illustration. Mycoplasmas are the smallest cellular organisms known (diameter 0.3-0.9 microns). They resemble bacteria i Stock Photo - Alamy
![Bacteria are the smallest living organisms on earth, with an average of micrometres long and micrometre thick. Bacteria are the smallest living organisms on earth, with an average of micrometres long and micrometre thick.](https://search-static.byjusweb.com/question-images/byjus/infinitestudent-images/ckeditor_assets/pictures/6686/content_image38.gif)