The evolution of sexual reproduction is a great puzzle in modern evolutionary biology. Many groups of eukaryotic organisms, especially most animals and plants, reproduce sexually. The evolution of sex between two organisms of the same species contains two related but different themes: its origin and its maintenance. However, since hypotheses for the origin of sex are difficult to test experimentally, most of the current work has focused on the maintenance of sexual reproduction. Biologists, including W. D. Hamilton, Alexei Kondrashov, and George C. Williams, have proposed various explanations for how sexual reproduction is maintained in a large set of different living things.
Probably not. some bacteria produce enzymes that break down hemoglobins in RBC.
I suggest that you should try C......
<span>The question says, 'which component of a virus is lacking in a cell. The answer is capsid. virus capsid are protein shell of a virus, they envelope the virus and protect it from harm. Cells does not have capsid, they have rigid cell wall instead. The rigid cell wall protect the cell from harm and also give the cell shape.</span>
