Answer: S- phase of cell cycle
Explanation:
Cell cycle is a cyclical process taken place in a cell leading to duplication of its DNA and division of cytoplasm to form two daughter cells.
The S phase of a cell cycle is an important part of the cycle which is found during interphase stage before either mitosis or meiosis.
The S phase of cell cycle is responsible for the replication of DNA. This replication DNA causes it to double before it enters mitosis or meiosis.
Answer: D. Species
Explanation:
Species is a group of population in which organisms have many common characteristics and they are capable of interbreeding and producing viable fertile offsprings. The members belonging to the same class and phylum have less common characteristics if they interbreed they may not produce viable fertile offsprings. Also, the organisms of the same kingdom have least common characteristics and will not have viable fertile offsprings after interbreeding.
Well, it's obvious, because without a transport system, cells wouldn't have the nutrients and things they needed!! And waste wouldn't be able to circulate out of cells.