Why does sexual reproduction introduce variety or variation ina species in 3 ways

Sexual reproduction unlike asexual reproduction provides genetic diversity because the sperm and egg that are produced contain different combinations of genes than the parent organisms. Ways in which sexual reproduction introduce a variation in a species are through; crossing over in meiosis, Independent assortment; and Gamete fusion 

An ecosystem is in a certain area and includes living and non living plus there is weather conditions and a biome is a large amount of area with similar climate.so ecosystem is based on weather and biome is based on the average climate 

Be prepared.experiment breaking point of rubber bands measured in certain amount of temperature communication

that's all i luck!