|
|
People who have myopia, or nearsightedness, are not able to see objects at a distance but only up close. It occurs when the cornea is either curved too steeply, the eye is too long, or both. This condition is progressive and worsens with time. More than 100 million people in the United States are nearsighted, but only 20% of those are born with the condition. Diet, eye exercise, drug therapy, and corrective lenses can all help manage nearsightedness.
Certain chemicals, after ingestion, can be converted by the body into cyanide. Most of these chemicals have been removed from the market, but some old nail polish remover, solvents, and plastics manufacturing solutions can contain these substances.
Asthma cases in Americans are about 75% higher today than they were in 1980.
Many of the drugs used by neuroscientists are derived from toxic plants and venomous animals (such as snakes, spiders, snails, and puffer fish).
As the western states of America were settled, pioneers often had to drink rancid water from ponds and other sources. This often resulted in chronic diarrhea, causing many cases of dehydration and death that could have been avoided if clean water had been available.
![The brain. (a) Superior (top) view. (b) Sagittal view of a sectioned brain to reveal internal featur](https://biology-forums.com/gallery/47/medium_14755_14_10_12_6_48_56_94051155.jpeg)
![The strange situation. The Strange Situation features a series of episodes in which (a) the mother l](https://biology-forums.com/gallery/47/medium_102911_23_06_15_12_00_56_22102589.png)