Why does loss of telomerase activity in humans lead to severe phenotypes in the first generation, while loss of telomerase activity in laboratory mice takes several generations to exhibit any sort of phenotype?

Human telomeres are short.

Explanation:

Telomeres are the short stretches of DNA present at the end of chromosome. The telomerase enzyme regulates the maintenance and replication of telomeres.

Human telomeres are short and the loss of telomerase activity can cause cancer and ageing problem in the humans. Mouse have long telomerase and loss of telomerase activity does not cause any serious harm.

answer: land bridge theory. land bridge theory held that shifting portions of dry land explained the finding of identical species on different continents. plate tectonic theory eventually eliminated the land bridge theory.

d concave shape of wave rock

explanation:

the concave shape of wave rock is a very good evidence that supports the evolution of earth due to chemical weathering. if we talk about structure of   wave rock, studies have estimated that it is around 2.7 billion years old. it also serves as the foundation of evidence that it was the place where australian continent began to form.

how the structure of wave rock was created?

studies suggest that structure of wave rock was created when the surrounded area was started to weather due to which deposition of material started on the part of land which now contains wave rock.

the structure of wave rock is considered to be one of the best-known landforms in australia. at the height of around 15 cm, there can be found flared slopes which formulate the margins of hyden rock. it is now assumed by geologists that wave rock was created by subsurface water-induced weathering and not by glaciers, waves or wind.

due to deposition of material over the period of long time, the wave rock became tougher and tougher due to weathering from surrounding terrain. this makes it a physical evidence that supports   the evolution of earth due to chemical weathering.

hope it !