Through the duplication and modification of pre-existing genes.
Answer:
Both
Explanation:
A person's skin color, hair color, dimples, freckles, and blood type are all examples of genetic variations that can occur in a human population. Examples of genetic variation in plants include the modified leaves of carnivorous plants and the development of flowers that resemble insects to lure plant pollinators. Even though in artificial selection, you take which genes are desired it is still passing genetic variation through offspring.
Answer:
If excess fertilizer is mixed with the water,it causes algal bloom as the number of phytoplankton increases at the initial stage due to intake of large amount of nutrients that are obtained from the fertilizers.
Explanation:
The nutrients that are mainly found in fertilizer are nitrogen and phosphorus that mainly helps for growth and development of plants.Fertilizers that are applied in the agricultural field are rich in nutrients and minerals that enters into the water stream through runoff and disturbs aquatic environment by reducing the oxygen content in the water due to algal bloom,emits odour and gas in the air,release toxic substance that kills many aquatic organisms,decrease water quality,increase level of pathogen that creates life threatening diseases etc.
