Which of the following statements is correct about LD50?(         )
A、Half of the lethal dose
B、Half of the toxic level
C、The dose that caused the death of half the experimental animals
D、The dose of killing half of the pathogenic microorganisms

5.4c How can you learn an online class according to the...

单项选择题5.4c How can you learn an online class according to the conversation?
A、You can learn at ant time.
B、You can learn through your mobile phone.
C、You can learn by sitting at home.
D、All of the above.

科学如同其字面含义，一定是分科别类的，是系统性的，只有在现有学科里的知识，才是科学。 A、正确 B、错误

单项选择题科学如同其字面含义，一定是分科别类的，是系统性的，只有在现有学科里的知识，才是科学。
A、正确
B、错误

存在论和认识论会影响对研究方法的选择。A．正确 B．错误

不定项选择 存在论和认识论会影响对研究方法的选择。