Answer:
In humans, genetic variations are caused because humans reproduce by a sexual life cycle which is termed as meiosis. In such a life cycle, the offspring receives half the chromosomes from the mother and half from the father. Crossing over and random assortment of chromosomes are two phenomenons which occur during meiosis. Due to these two phenomenons, genetic variations are caused.
During crossing over, the exchange of DNA segments between the homologous chromosomes takes place which brings about the genetic variations.
Answer: The main cause of the extinctions is the destruction of natural habitats by human activities, such as cutting down forests and converting land into fields for farming. Due to human activities, populations of many species have become small and isolated.
Explanation:
It is the trigeminal. check my spelling though.
Answer:
The given question is incomplete, as there is no options provided, and are not available anywhere. But in general, if a forest ecosystem has not experienced any kind of disturbances or natural disasters in the last 100 years then the various plants and animals species dwelling in that forest are reasonably stable.
Explanation:
A forest ecosystem is usually defined as a distinct ecosystem that is comprised of trees, plants and animals, and micro-organisms, in an area that interacts with the abiotic factors such as water, soil in order to survive.
If a forest ecosystem is not disturbed by any anthropogenic or natural disasters for the past 100 years, then the species living in this ecosystem becomes reasonably very stable. They will be adapting to the environment and habitat becomes permanent. There will not occur much physiological and morphological variation in these species.
