I believe it is the answer is C
1. <span>composed of cells with cell walls
2. </span><span>Vertebrates contain a backbone, while invertebrates do not.</span>
I believe the answer is B. They were no longer able to acquire the necessary characteristics for survival in a changing environment. I think it is B. because trilobites mostly went extinct because of the event that wiped out 95% of Earth's species. So they didn't have the characteristics to survive. Hope I helped!
Skin is made of 3 layers
the top Layer that is exposed to air is the epydermis
the middle layer is the dermis
the lowest and largest layer is the HYPODERMIS. This is the innermost and farthest from the surface of the skin
Explanation:
With few exceptions, cellular membranes — including plasma membranes and internal membranes — are made of glycerophospholipids, molecules composed of glycerol, a phosphate group, and two fatty acid chains. Glycerol is a three-carbon molecule that functions as the backbone of these membrane lipids.