Cnidarians were the first phylum that scientists saw tissue level organization in. Tissue level organization meaning cells all of one type start to function in a unified way.
All living organisms are composed of building blocks termed as cells. Cells that perform similar functions are grouped together to form tissue.
The phylum where tissue-level of organization is seen first is Cnidaria. This phylum contains approximately 10,000 species ( such as jellyfish, sea anemones, corals).
Cnidarians have cells that are organized into two types of tissues, which occur in two layers. External tissue layer is ectoderm and inner tissue layer is endoderm.
1. RNA has ribose sugar instead of deoxyribose 2. RNA is generally single-stranded instead of double-stranded 3. RNA contains uracil in place of thymine
<em>'Many geologists believe that as the Earth cooled the heavier, denser materials sank to the center and the lighter materials rose to the top. Because of this, the crust is made of the lightest materials (rock- basalts and granites) and the core consists of heavy metals (nickel and iron).'</em>
