The right options are;
are disease-causing microorganisms
can be fatal
A pathogens is any substance or organism especially microorganisms that are capable of causing diseases. Pathogens include; bacteria, viruses, protozoa or fungi. Microorganisms are not considered to be pathogenic until they have reached a population size that is large enough to cause disease. Pathogens can be fatal and can be treated. Pathogens are diverse and they occupy essentially every environment.
They may have ran out of oxygen, or they may not have been water dwelling snails, as not all are, lack of food, no flow of water into and out of the tank would cause them to run out of oxygen.
The Main Organs include: Salivary, glands,Zero esophagus, Sstomach, Small intestine,Large Intestine and Rectum
From what I know, nicotine is a stimulant. It's not much, but I hope it gets you close to a answer. :3
The answer is the 3rd option:))
