Genes are the foundation for biological organisms. If I had the genes of a dolphin I would have been able to put half of my brain to sleep and keep the other half awake the way dolphins do but I can't do it because I don't have the genes of a dolphin. If I had the genes of a chameleon I would have been able to change the colour of my skin at will but I can't do it because I don't have the genes of a chameleon. If I had the genes of a tardigrade, I could survive in the vacuum of space without a space suit. I can't do it because I don't have the genes of a tardigrade. I could cite millions of cases like this.
If I was put in a very hot environment or very cold environment I would die. This is because my body can maintain homeostasis only within a narrow temperature range. If I had free will, I would have been fine at 1000 degrees Celsius and at minus 270 degrees Celsius. If I was put in a vat of acid, I would die because my body would be consumed by the acid.
I depend on nutrients for my existence. If I was deprived of oxygen, water and food I would die. If I had free will I would have been able to live without consuming any oxygen, water and food. I hate having to breathe, drink and eat. I long to live without consuming anything but I can't do it because I lack free will.
My experiences have a huge effect on all of my choices. I am having this conversation with you in English. If I had never learned English, it would not have been possible for me to have this conversation with you in English. I would love to be fluent in the 600+ languages that are still around without having to learn them.
Every single choice made by organisms is the result of their genes, environments, nutrients, and experiences.
If I have a stroke giving me locked-in syndrome, I would not be able to go for a walk. If someone kidnaps me and ties me up, I would not be able to go for a walk. If someone knocks me unconscious, I would not even have the thought of going for a walk, never mind going for a walk. The examples are endless.
As I suffer from depression, I am unable to sleep well.
I am completely certain of the following:
1. I am conscious.
2. I am typing in English.
3. I am not all-knowing.
4. I am not all-powerful.
5. I change.
6. I can't do lots of things I really want to do e.g. go back in time and prevent all suffering, inequality, injustice, and deaths and make all living things forever happy.
7. I do some things even though I don't want to do them. Here are some things I have done, currently do or will do even though I don't want to do them:
14. Get ill
15. Get injured
23. Be conceived
24. Be born
25. Remember some events that I don't want to remember
26. Forget information that I want to remember
I am almost certain of the following:
1. I and all the other organisms currently alive will die. Every second brings all organisms closer to death.
2. My body, other organisms, the Earth and the Universe really exist and they are not part of a simulation or hallucination or dream or illusion. It is impossible to be completely certain about this.
3. Other organisms e.g. humans, cows, dogs, cats, chickens, pigs, lions, elephants, butterflies, whales, dolphins, etc. are conscious.
4. Being a vegan is more ethical than being a vegetarian and being a vegetarian is more ethical than being an omnivore.
5. Gods do not exist.
6. Souls do not exist.
7. Reincarnation does not happen.
8. Resurrection does not happen.
10. Organisms evolved and were not created by God or Gods.
11. 99.9% of all the species to evolve so far on Earth became extinct in 5 mass extinctions long before humans evolved.
12. Humans and other organisms do not have free will. Our wills are determined and constrained by our genes, environments, nutrients, and experiences. The reason I have put this one in the almost certain category is that it is possible that bodies, genes, cells, stars, planets, moons, galaxies, universes, may not actually exist. These things could be part of a simulation or dream or hallucination or illusion. It is impossible to know with complete certainty. I could be a solipsistic soul experiencing the illusion of being in a human body - I have no way to test this idea.