A．In science, it is not difficult to distinguish fact f……

单项选择题An operating system is no guarantee of online security probably because ______.

单项选择题The best title for the passage would be ______.

单项选择题To define science we may simply call it ______.

单项选择题Pure science, leading to the construction of a microscope, ______.

单项选择题According to the passage, the use of Antarctic krill as a food is an innovation whose future is ______.

单项选择题A scientist being interested in adding to our general knowledge about oxygen would probably call his approach ______.

单项选择题The cultural communication problems are becoming especially urgent for ______.

单项选择题The best title for the passage would be ______.

单项选择题It can be inferred from the passage that the author assesses the truth about opaque-2-maize in that ______.

单项选择题We learn from the first paragraph that ______.