Advantage: Dichotomous keys are very useful because they allow non-expert users to identify organisms by directing them to look at the known, important organisms. Disadvantage: Disadvantage of dichotomous keys is that if a single wrong decision is made at any juncture, a wrong identification will result. Sometimes it becomes obvious that an error has been made, and you can retrace your steps until you get back on the right track, but this is not always the case
Treehouses are built on the stem and the three branches, which do not grow in length, only in width. Trees grow in length only in the area of the buds, which are located at the ends of branches.
Maybe it is easier to understand this if you imagine that you put a small house replica on the palm of your hand and that your fingers are constantly growing from their tips. So, the house on your palm would not move, only your fingers, (the analogy to the three top buds) would become longer.
Answer:
When a long-term environmental change occurs, certain individuals in a population will be better adapted for the new environment than others. ... Over many generations, these favorable adaptations build up in a population. This may lead to speciation, which is the development of a new species.