Nanotechnology is a fashionable word these days. The name "nano"  comes from the size of molecules, which are measured in nanometers--or one billionth of a meter. Through operating the atoms and molecules, scientists can change the nature of common materials and even create new materials that have new properties. But scientists are concerned about its possible risks to our daily lives. Clothing merchants claim their nanocloth keeps our bodies warmer in winter, saving us from needing thick coats. Vitamin companies boast their nanopills are easier to absorb. Home decoration companies suggest you use their nanopaint, which has no smell, is waterproof, and free from poisonous substances. Nanomaterials are making our lives better, its creators say. The US National Science Foundation predicts nanotechnology research will grow into a US $-trillion industry over the next 10 years. But  ly little is known about the potential health and environmental effects of the tiny particles. Just atoms wide, they are small enough to penetrate cells easily in lungs, brains and other organs. US bestseller "Prey", written by Michael Crichton, paints a doomsday in which a group of tiny nanomachines escapes the lab and threatens to take control of humanity.  Studies have shown that some nanoparticles can be poisonous to animal cells. There are fears that exposure can cause breathing problems, since nanoparticles could be taken in through the nose, causing unknown problems to brain cells. Scientists also fear that nanoparticles placed on the skin could damage DNA. "No one knows, and that's the problem," said Pat Mooney, director of the ETC Group. "People are rubbing them on the skin as sunscreens and as cosmetics." Mooney's group is calling for products such as sunscreen, that are directly absorbed into the body to be _ taken _ off _ the _ shelf until they're proved safe. Studies have made it clear that  _  .
exposure to nanoparticles can damage DNA rubbing nano cosmetics on the skin can help control skin diseases all nanoparticles can't be poisonous to animal cells the nanoparticles have bad effects on health and environment
Question: Nanotechnology is a fashionable word these days. The name "nano"  comes from the size of molecules, which are measured in nanometers--or one billionth of a meter. Through operating the atoms and molecules, scientists can change the nature of common materials and even create new materials that have new properties. But scientists are concerned about its possible risks to our daily lives. Clothing merchants claim their nanocloth keeps our bodies warmer in winter, saving us from needing thick coats. Vitamin companies boast their nanopills are easier to absorb. Home decoration companies suggest you use their nanopaint, which has no smell, is waterproof, and free from poisonous substances. Nanomaterials are making our lives better, its creators say. The US National Science Foundation predicts nanotechnology research will grow into a US $-trillion industry over the next 10 years. But  ly little is known about the potential health and environmental effects of the tiny particles. Just atoms wide, they are small enough to penetrate cells easily in lungs, brains and other organs. US bestseller "Prey", written by Michael Crichton, paints a doomsday in which a group of tiny nanomachines escapes the lab and threatens to take control of humanity.  Studies have shown that some nanoparticles can be poisonous to animal cells. There are fears that exposure can cause breathing problems, since nanoparticles could be taken in through the nose, causing unknown problems to brain cells. Scientists also fear that nanoparticles placed on the skin could damage DNA. "No one knows, and that's the problem," said Pat Mooney, director of the ETC Group. "People are rubbing them on the skin as sunscreens and as cosmetics." Mooney's group is calling for products such as sunscreen, that are directly absorbed into the body to be _ taken _ off _ the _ shelf until they're proved safe. Studies have made it clear that  _  .
A. exposure to nanoparticles can damage DNA
B. rubbing nano cosmetics on the skin can help control skin diseases
C. all nanoparticles can't be poisonous to animal cells
D. the nanoparticles have bad effects on health and environment
Answer: