🦠 Did You Know? A disease isn't just a random illness. It's a specific kind of illness with its very own set of symptoms.

In ancient times, people had some pretty wild theories about what caused diseases. Imagine thinking breathing bad air caused malaria! 😆 Thankfully, we've come a long way since then. Diseases generally have three primary causes 

• Genetic: It's all in your genes! Sometimes the alleles (versions of genes) a person has can make them more prone to certain diseases.
• Environmental: Pollution, chemicals, radiation... the environment can sometimes play a big role in making us sick.
• Infection with a pathogen: These are the sneaky microorganisms that can enter our bodies and cause harm.

🌍 Real-world example: Think of genes as a computer's hardware, the environment as the software, and pathogens as those annoying malware or viruses that crash your system!

Pathogens are the bad guys of the microorganism world! They're organisms that cause disease. Unlike tapeworms which we can see and are parasites, pathogens are micro-sized and can't be seen without a microscope.

Key Point: Pathogens have this nasty habit of multiplying once they get inside our bodies.

🍔 Real-world example: Imagine ordering a single burger and suddenly finding your plate filled with dozens of them! That's kinda how pathogens multiply inside our bodies.