This is because it has many parts, arteries, and tubes that pass blood around the body. It is hard because it has many parts which are difficult to be cut open. Hope I helped!
From single-celled ancestors, they evolved into a riot of complexity and diversity. An estimated seven million species of animals live on earth today, ranging from tubeworms at the bottom of the ocean to elephants lumbering across the African savanna.
Transcription<span> is the synthesis of an RNA strand from a </span>DNA<span> template. A gene's protein building instructions are </span>transcribed<span> to messenger RNA (mRNA). mRNA carries the code from </span>DNA<span> to the ribosomes where translation into a protein occurs</span>
