They have to adapt to the water, the animals in the ocean, the way they hear and see.
Answer:
gene flow
Explanation:
Gene flow, in simple terms, is a transfer of gene from one population to another. Also called as migration, where there is movement of individuals, and the genetic material they carry from one population to another. It also involves successful breeding of these individuals in their new locations. When people with sickle cell anemia were brought into the US, transfer of the gene responsible for sickle cell disease changed the frequency of the sickle cell allele in overall US population.
Answer:
Due to presence at early days of the planet.
Explanation:
We only find the remains of single celled organisms in the oldest fossils because the single celled organisms are the organisms that were present in the early days of this planet. These single celled microbes were present about 3.7 billion years ago while on the other hand, the oldest rocks are only a little older i. e. 3.8 billion years so these single celled organisms are considered as oldest fossils on this planet.
