When a new substance has formed during a chemical reaction, it is considered to be what type of change ?

The population of bacteria in a petri dish doubles every 40 seconds. the population of the bacteria is initially 400 organisms. what unit is most appropriate for the time at which the number of bacteria is 300? hour bacteria per hour second bacteria per second

Guard cells control which event? the growth of plants capture of solar energy gas exchange in leaves water absorption in roots

The same agricultural practices are used in every country of the world. select the best answer from the choices provided t f