2. You will not see an organism change overnight. Evolution is most often a slow process that can take many years for a change to occur. There can be changes occurring internally, such as changes in DNA, that we cannot immediately see, but are still occurring. There are also fossils, which help to support evolution that has happened in the past.
3. The fossil record does not just tell us that lots of plants and animals died in the past. It tells us how organisms used to look like, and we can compare them over the years to track differences. We are able to tell how they have evolved and which parts have changed in relation to things such as bones and structure. For example whether or not the animal had wings, or if it was a land or sea creature, and whether or not it is still that way today.
4. Something like the blowhole of a whale develops in stages, because evolution is not something that occurs overnight. It is a process that can take many years. Such as the nostril moving to the top of the head for the whale, it slowly moved over the years to make it easier for the whale to breathe while in the water. Even though it did not serve any purpose until it was fully formed, it serves a purpose now. We also have vestigial structures that used to serve a purpose, but no longer do. Just because currently it is not serving a purpose, it could in the future, or could have served an important purpose in the past.