Tracheotomy refers to creating an opening in the neck in order to place a tube into a person's windpipe.
Punnet squares are a useful tool for predicting what the offspring will look like when mating plants or animals. Reginald Crundall Punnett, a mathematician, came up with these in 1905, long after Mendel's experiments. Let's take a look at how Punnet squares work using the yellow and green peas example from im not sure about the tree by three thing but maybe this will help :)
The endosymbiotic hypothesis concerns the origin of mitochondria and chloroplasts, two organelles contained within various eukaryotic cells. According to this hypothesis, these organelles originated as separate prokaryotic organisms that were taken inside a primordial eukaryotic cell.
