<span>B. Marsupials. </span>Amniotic eggs is a unique kind of egg because they possess a semipermeable shell to protect the egg but it also allows gas exchange. Inside an amniotic egg contains the amnion, chorion and allantois. Animals that lay amniotic eggs are called amniotes, which include reptiles, birds, dinosaurs, monotremes (platypus).
Answer:
This is allopatric speciation. The organisms were separated from each other by the containers. The separation caused them to evolve to the point that they were more likely to mate with each other than with a member of another tank.
Explanation:
Answer:
Explanation:Following are the techniques or methods or approaches we can say that were used by the scientists to determine the geologic age:
1. Relative age dating
2. Absolute age dating.
3. Radiation measurement.
4. Stratigraphic superposition.
5. The fossil record.
The scientists used the method of relative dating to divide Earth's past in different chunks of time when alike organisms were on Earth. After that, to discover the actual number of years ago that events occurred, the scientists used the method of absolute dating.
Answer:
Innate immunity is a non-specific immune system which provides defence against any pathogenic microorganism in early stages. It includes physical barrier such as skin, chemical barriers such as saliva, tears, et cetera, phagocytic cells such as macrophages, et cetera.
Acquired immune system is the one which develops after exposure to pathogen or antigen. It is highly specific in nature. It includes B-lymphocytes and T-lymphocytes. It includes the production of antibodies.
Vaccines are used to develop acquired immunity in people. The process is termed as vaccination or immunisation. Heat-killed or weakened pathogen or antigen is inserted into a person after which a person develops antibodies and memory cells against that pathogen or disease. So, the immune system acts more vigorously against that pathogen in secondary infection.
Thus, a person becomes immunised.
