2 then it later divided to 4
Answer:
Living organisms that are heterotrophic include all animals and fungi, some bacteria and protists, and many parasitic plants. The term heterotroph arose in microbiology in 1946 as part of a classification of microorganisms based on their type of nutrition.
a cell is the smallest structural and functional unit of an organism
Answer:
The correct answer would be non-disjunction.
Down syndrome refers to the genetic disease caused by the non-disjunction of chromosome number 21.
Non-disjunction refers to the event in which the homologous chromosomes or sister chromatids fail to separate properly during a cell division.
In Down syndrome, the sister chromatids of chromosome 21 fail to separate properly which results in the formation of a gamete with 2 copies of chromosome 21.
When this gamete fertilizes with another gamete, it results in the formation of a zygote with 47 chromosomes, that is, 46 chromosomes + extra copy of chromosome 21.
