 To stay alive, cells need to absorb nutrients inside and throw waste outside. Single cell organisms easily do this by diffusion. But that doesn't work for complex multicellular organisms like you and me because diffusion is too slow and doesn't work at large distances. So how do we stay alive? By carrying out life processes. The first one is nutrition where we eat and digest the food to get the nutrients. The next one is transportation where we transport the nutrients to all the cells of the body. Then comes respiration where the cells break down the nutrients releasing energy and some waste products. And then finally excretion where all the waste products are thrown out of the body. The same is true for plants as well. For plants, they create their own food and absorb nutrients from the soil. So that's their nutrition. Then they transport that food to all the cells. The cells do respiration to break the food to get energy and some waste products. And finally they throw these waste products out of their body. And in this chapter we will dive deeper into each of these processes and see how amazing they are. And hopefully you will be able to appreciate how the different parts of the body work together every single minute of your life to keep you alive.