Prezygotic isolation is a type of reproductive isolation that occurs before the formation of a zygote can take place. In most cases mating does not even occur. Forms of prezygotic isolation include spatial, behavioral, mechanical and temporal isolation.
Postzygotic isolation on the other hand occurs after members of two different species have mated and produced a zygote. Forms of postzygotic isolation includes; hybrid sterility, hybrid inviability and hybrid breakdown.
Therefore; Prezygotic isolation prevents the fertilization of eggs while postzygotic isolation prevents the formation of fertile offspring.

4 0

3 years ago

Fossilized stromatolites

Cerrena [4.2K]

Answer:

(B) resemble structures formed by bacterial communities that are found today in some shallow marine bays.

Explanation:

Extant stromatolites represent real "living fossils" for they are decendents of ancient forms that are associated with one of the first living forms on earth. Particularly, stromatolites are real bacteria communities where the autotrophic organism of the community are represented by cyanobacteria, which live along with heterotrophic bacteria. This clearly indicates that fossilized stromatolites points to bacteria (prokaryotes) as the first living things on earth (dated with not less than 3.5 billion year old)

Nowadays, stromatolites with cyanobacteria allows to reconstruct and understand fossilized forms. These current structures live in shallow marines ambients (e.g. Australia) but also in continental salt flats (e.g. Argentina) where few others bacteria can survive to these extreme conditions (high light exposure and salt concentration).

6 0

3 years ago

An explorer discovers an island dominated by a geologic structure with gently sloping sides that formed over a hotspot? Which of

s2008m [1.1K]

The explorer has discovered "A shield volcano".

6 0

3 years ago