Answer: option A, B, C at correct
Explanation:
All animals have collagen. Collagen is found exclusively in all animals. It is the main structures protein that is found in the connection tissues of animals.
Animals do possess embryos that undergoes gastrulation where the digestive cavity and germ layers are formed, these then develop into certain tissue systems, organs etc
Animals are heterotrophs in that they are unable to symthesize their own food but rather depend on plants which are autotrophs for their food and they also lack cell wall which differentiates them from plants. Not all animals are mobile for example, sponges.
