Answer:
Increase: plentiful roaming space, abundant food sources, elimination of predators, lack of competition.
Decrease: severe drought, habitat destruction, disease outbreak.
Explanation:
Plentiful roaming space increases the carrying capacity because it enables that everyone has enough space to operate and live in.
Severe drought decreses the carrying capacity because it will result in food and water shortages.
Abundant food sources will increase the carrying capacity because they will enable everyone to be fed without any problem.
Habitat destruction will decrease the carrying capacity because it will result in lack of natural resources and bad quality of life.
Elimination of predators will increase the carrying capacity because the safety will improve.
Lack of competition will increase the carrying capacity because all of the resources will be available.
Disease outbreak will decrese the carrying capacity because it will lead to sick population in bad condition, and possibly large scale death.
Explanation:
In a general way cells communication to each other through chemical signal which can be regarded as their language. Hormones, compounds and neurotransmitters behave like words that are spoken because they tell the cell about its environment and they also pass messages to the cells and the cell acts on the signal received. Each cells has receptors through which they detect different actions to be taken or signals that needs to be responded to, so they are always underground biological conversations.
Your question is rather unclear but from what I can tell either there were not an even amount of Petri dishes or some of them were left open while others were not.