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.
The answer is d. atmosphere < leaves < roots < soil
I believe the correct answer is the third circle
Movement : kinesis
Behavior: It is sometimes called a roly-poly due to its ability to roll into ball when disturbed
Microscopes
Before the development of microscopes, the existence of cellular life was unknown. By examining a piece of cork, Robert Hooke first saw and named cells. Antony van Leeuwenhoek was the first person to see living cells.
