Questions

Species richness is generally lower in the Arctic than at lower latitudes, and richness also tends to decline from the low to high Arctic.Many hypotheses have been advanced to explain the overall decline of biodiversity with increasing latitude, although there is still no consensus about a mechanistic explanation. Abiotic factors include lower available energy and area at high latitudes, and the relatively young age of Arctic ecosystems.

Here in the above given question, the mistake is "the is reapeated twice" before mistake.

The data unit created at the application layer is called a message, at the transport layer the data unit created is called either a segment or an user datagram, at the network layer the data unit created is called the datagram, at the data link layer the datagram is encapsulated in to a frame and finally transmitted as signals along the transmission media.