Question: why dont you use Monkeys for experiments because they are more like humans than worms

Rachel McMullan answered on 16 Nov 2015:

It’s true monkeys are a lot more like humans than worms but there are lots of reasons why we start with worms. Firstly worms are small and cheap to work with in the lab whereas monkeys are quite big and really expensive. Secondly worms only take about three days to grow from an egg to an adult and monkeys take a lot longer. Thirdly because monkeys are so similar to humans they are nearly as complicated and have nearly as many brain cells. Worms only have 302 brain cells so they’re much simpler and easier to understand. Finally there are really strict ethical rules about working with monkeys (and rightly so).
It is possible that in the future we would want to know things we can’t discover using worms but by using worms we can do experiments really quickly and cheaply and use the information we get to design better experiments that involve using less animals.