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.
Erosion of sand n dirt and it ca cause sinkholes
Give us Choices, but I’m guessing it’s limiting factor
The correct answer is D. Bird flu.
Polio and smallpox are very rare today as they were eradicated hundreds of years ago and TB has been around for maybe thousands of years. Bird f!u was discovered in 1957.