The Sinoatrial node (SA) - a collection of specialized cells and is located in the holder wall of the right atrium
Answer:
Speciation occurs at terminal population groups
Explanation:
A ring species represents a group of organism that has moved beyond a geographic barrier to produce a ring shaped distribution. This population is contiguous and there exists no barrier to gene flow anywhere in the ring except at the terminal populations.
Speciation is demonstrated in the terminal population has become sympatric and it does not interbreed even if they are connected by chain of intergrading or interbreeding populations
In an ecosystem, two factors are being classified which are the abiotic and the biotic factors. Both of these factors play an important role in order to balance the ecosystem and maintain the harmony of the living things therein. The environment includes the abiotic factors which are the sunlight, weather, water, air, and all other factors which are not living but contribute to the growth and development of the living ones. For example, plants cannot live without water, sunlight and carbon dioxide. The effects that humans have on the environment is both good and bad. Humans also play an important role in maintaining the environment, and they also have the capability to endanger it.
