Edward jenner discovered vaccinations. he found that some of the dairymaids who worked with cows had suffered lesions on their hands, and that these dairymaids were immune to the more severe smallpox. which best explains why the dairymaids were immune to smallpox?

1they did not interact with many people so they were not exposed to the pathogen.

2they frequently washed their hands so they were able to wash away the pathogen.

3they were exposed to cowpox, and the substance their body produced to fight cowpox also attacked smallpox.

4they breathed the air around the cows that carried an antipathogen in it that destroyed the pathogen.

The correct answer is option 3- They were exposed to cowpox, and the substance their body produced to fight cowpox also attacked smallpox.

When Jenner discovered that the milk maid who suffered from cowpox were immune to small pox, he got convinced that the occurrence of cow pox created immunity against small pox infection. To study this further, he took a sample of fluid from a cowpox pustule and injected it in a boy and at that moment he invented the principle of immunity.

the answer is 1. photosynthesis. glad to

answer: ice crystals in air

the water from the water body or another source of water gets evaporated as water vapor as an effect of heat on water. these water vapor rises in the upper layers of the earth atmosphere under high atmospheric pressure. the atmospheric pressure of these water molecules starts to decrease due to the effect of cold air. the invisible water vapor condenses into visible water droplets and ice crystals.these ice crystals and water droplets being less denser than the surrounding air floats on air as clouds.