system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: When it is said that Humans share 98% of their DNA with chimps, 70% with slugs, and 50% with bananas, what does this actually mean?
gpt
If you wanted to build a motor vehicle, you need an engine, a chassis and a method of transforming the energy from the engine into movement of the chassis.

An aeroplane and a car are very different, but both have a chassis, an engine (at least one) and a method of transforming energy into movement (propellers or jets in the case of the aeroplane, a drive-shaft and wheels in the case of the car). Apart from that they don't have many other similarities in how they operate, what they can do or what they are used for.

A bus and a car share many more features in common, and in terms of the components they require to work are very much the same (at least much more so than an aeroplane and a car). However, they are very different machines, have different methods of operation and are used for different things.

A family Ford and and a luxury Aston Martin are, apart from physically, almost identical machines, especially when compared to an aeroplane or even a bus. Very similar components, similar mode of operation and similar purpose. However, the differences are still very large even though they are basically the same machine, and you would not confuse one with the other.

At the end of the day, they are all motor vehicles, because they all have engines, a chassis and a method of using the energy of the engine to move the chassis, but as soon as you start introducing differences between motor vehicles, even relatively small ones, you  can get vastly different products.

Life is like this too. There are many basic traits that are shared by all life-forms, seen through similarities in DNA. This is how we know they are life-forms, in the same way that an engine, a chassis and a way of transferring energy into movement are how we know something is a motor vehicle. However, differences in DNA, even small ones, result in very different forms of life. So when we say that we share 98% of our DNA with chimps as opposed to 50% with a banana, it's sort of the same as saying that a Ferrari is extremely similar to a Toyota, but has a lot less in common with a fishing boat, even though they're all motor vehicles.