Answer:
The answer is D. Digestion
Speciation is the process by which new species form. It occurs when groups in a species become reproductively isolated and diverge. In allopatric speciation, groups from an ancestral population evolve into separate species due to a period of geographical separation.
Answer:
<h2>c. Division of these two groups occurred after the protostome developmental sequence appeared. </h2>
Explanation:
- Protosomes are such types of organisms in which the mouth part developed first during embryonic development.
- Those animals in which anus develop first are known as deuterostomes.
- This differentiation takes place during the embryonic development of the organisms.
- Since lophotrochozoan and Ecdysozoa both are protostomes animals and categorized on the basis of molecular evidence.
- Thus these two groups were formed after the appearance of the protostomes.
Answer:
Most cells within planarians tend to be very close to their gastrovascular cavity, in addition to their external environments. Also, planarians have the ability for oxygen and carbon dioxide to diffuse through the cells on their body walls: this makes it unnecessary for these varieties of flatworms to need a dedicated bodily system.
I think the deficiency of dedicated respiratory and circulatory systems in Planarians does not cause a problem because none of their cells are far removed from the gastrovascular cavity or from the external environment. Planarians are free-living flatworms and form the class Turbellarians in the Phylum Platyhelminthes. Flatworms have three tissue layers, that is the ectoderm, mesoderm, and endoderm.
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Explanation:
