It something that tests your knowledge it's like a quiz
Answer: Vaccines- The history
Explanation: Vaccines are shots of medicine that are used to prevent someone from catching a strain or virus. They are used worldwide, and are given to mostly children and elderly, to protect their immune systems.
What is the history of vaccines? The first vaccine was developed in 1796 by Edward Jenner. He made it to find a cure to smallpox. He tested it on a 13-year-old infected with smallpox, and the boy later showed immunity to smallpox. In 1798, the smallpox vaccine was first released to the public.
Sorry if it wasn't as much as you wanted, I don't have much time
Answer:
Randomized
Explanation:
Observational Studies and Randomized Trials are two ideal ways of determining the outcome of certain tests.
In the Observational course the study is conducted in a true to life scenario and the result of what happens is recorded. Meanwhile, in the Randomized Trial there purposefully placed conditions that are ideal and these are evaluated after specific interventions.
Since the pool manager did not let different pools grow algae at will before putting in the chemical this study would not be considered observational. Instead he set up three different pools of the same size with the similar amount of contaminants and then tested the algaecide. This classifies this as a Randomized Trial.
The Apollo 13 was the 3rd mission to land the moon. The explosion of the oxygen tank effected this because the crew was forced to orbit the moon and land safely back to Earth without landing on the moon
The answer is E because u can’t put a period at the end of that sentence
