Scratch

Hello everybody.

Well, I'm making a bacteria tank in Scratch, but there are problems.

Well first of all, I'd like to make the bacterias duplicate themselves in an interval, but I didn't find how to do it, how can I make an existing agent duplicate himself while executing instead of manually duplicating the sprites.

Also there are virus throughout the "tank" and those virus will infect the bacterias and release themselves (one virus infect a bacteria, later the infected bacteria releases 3 virus and so on), which would be a similar schema to the bacteria.

Can someone tell me how is this possible?

Thanks in advance