Fredrick Griffith, He did an experiment with virulent and non-virulent strains of pneumonia. He heat killed the virulent strain, making it harmless and then mixed it with the non-virulent strain. When he inoculated mice with the mixture, the mice died, This meant that the non-virulent bacteria had picked up some genetic material from the killed bacteria - they had been transformed.
Answer:
Explanation:
The animals are used for examining and determining the effect of a particular new drug for the treatment of the diseases and disorders before they are examined over humans. This practice is called as clinical trial.
The ethical issue associated with given type of testing is that animals have right to live and survive. They should not be subjected to the treatment where they experience harm or even death.
The correct answer is "limited prey is driving the bears to seek food in human settlements".
Due to the warming of the Arctic waters, the ice is melting, resulting in a serious decline of floating winter ice. Polar bears need these floating parts of ice to hunt, therefore this new situation limits the hunting opportunities of the bears. That is why polar bears are driven to human settlements to look for food.
The scientific method includes experimental method, comparative and descriptive method of investigation.
Their limitation include
descriptive method of investigation
It cannot be used to correct variable or be used to determine causes and effect of the problem
experimental method of investigation
IT might create an artificial situation that do not always represent the real life situation
comparative method of investigation
It is not easy to control other variables that might influence the study
