Edward Jenner inferred that a person who once had small pox cannot have it once again. So something is there in these persons which grows after the initial infection which interferes with the secondary infection resisting it.
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Explanation:</u></h3>
Edward Jenner is called the Father of Vaccination. Jenner noticed that the milkmaids who deal with the cows all the time don't generally suffer from the cowpox or small pox. Then as an Experiment, he took some sample from the pustules of the cow having pox and then cleaned it and injected the sample into a healthy child. Then when everyone of the locality suffered from the same disease, that child remained healthy. So that lead to infer that there are something in the pustule which lead to resist the secondary infection of this disease. So this lead to the invention of vaccines.
Answer:
Soil pollution- Soil pollution is defined as the presence of toxic chemicals in soil
it could pose a threat to humans, etc...
caused by the presence of xenobiotic chemicals
(A xenobiotic is a chemical substance found within an organism that is not naturally produced or expected to be present within the organism.)
or other alteration in the natural soil environment. It is typically caused by industrial activity, agricultural chemicals or improper disposal of waste.
Air pollution- Air pollution is a mixture of solid particles and gases in the air.
Car emissions, chemicals from factories, dust, pollen and mold spores may be suspended as particles.
Explanation:
Answer:
The nucleus
Explanation:
The nucleus contains chromosomes that contain genes
<span>The answer is nerve net.
Jellyfish has a nerve net that surrounds its
whole body. It makes a series of interconnected neurons that form net-like structure. This net surrounds the whole body of the jellyfish. Some jellyfish may have sensory structures, motor nerve net, and diffuse nerve net. Sensory structures receive environment signals and send them through diffuse nerve net to motor nerve net that activates muscle contractions.</span>
Answer:
brown bear
Explanation:
Brown bears have long, intimidating claws. However, since they are not retractable, they are relatively blunt and are usually used for digging. These bears are incredibly strong, able to break the necks of many large prey with one powerful blow. Their thick fur and layer of fat help to insulate them against the extreme cold temperatures of their habitat.
