The answer is skin
The first line of defence is your innate immune system. Level one of this system consists of physical barriers like your skin and the mucosal lining in your respiratory tract. The tears, sweat, saliva and mucous produced by the skin and mucosal lining are part of that physical barrier, too.
Answer:
Offer more healthy foods in the cafeteria and raise the prices on unhealthy foods because young people need money to go out
Explanation:
Answer:
Common causes of blindness are diabetic neuropathy, glaucoma and cataracts.
Explanation:
Blindness refers to the complete lack of functional vision.It occurs when an inadequate amount of light hits the retina, or the information has not been delivered to the brain correctly.
Complete blindness : characterized by a complete and total loss of vision. Merck Manuals reports that legal blindness is defined as having equal to or worse than a 20/200 visual acuity in the better eye. Having a visual acuity of 20/200 means that someone with normal vision can see an object at 200 feet, and a person with impaired vision can see at a distance no further than 20 feet. Several different diseases can cause complete blindness; some develop later in life and some are present at birth. The leading cause of blindness in the United States is diabetes, according to the National Eye Institute. Diabetes causes diabetic retinopathy, which results in destruction of the retina. Other causes of complete blindness include age-related macular degeneration, which the National Eye Institute calls the most common cause of blindness in adults who are 60 or older; cataracts, which obstructs light from hitting the retina because of opaque patches on a lens; and glaucoma, which causes blindness due to damage to the optic nerve.
Color Blindness
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People who have color blindness, also called dyschromatopsia, are unable to distinguish certain colors. This type of blindness more commonly affects men than women. Merck Manuals reports that the most common form of color blindness is red-green color blindness, which makes it difficult to distinguish certain shades of red and green. Color blindness is almost always present at birth, and is usually caused by the presence of a defective gene on the X chromosome. The reason that more men are affected by color blindness than women is that women have two X chromosomes; thus, even if they are "carriers" of a bad gene, their other X chromosome usually has a functional gene. Because men have only one X chromosome, the presence of one bad gene is sufficient to cause color blindness. Defective retinal cells result in some forms of color blindness; other forms are caused by defects in the optic nerve.
Night Blindness
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Night blindness is vision impairment that occurs at night or when light is dim. It does not generally result in a complete lack of vision but significantly impaired vision. People with night blindness often have difficulty driving at night or seeing stars. Several different factors cause night blindness, according to the University of Maryland Medical Center. These factors include cataracts, birth defects, a vitamin A deficiency, or a retinal disease called retinitis pigmentosa
Answer:
Modern people are using the Earth for many things like farming, technology, art, and more.
Explanation:
Farming is a form of agriculture, people who farm can make money off of selling their crops, and they can also feed themselves.
Technology is a mix of mathematics, science, and the arts. Without technology, phones, laptops, cars, and other electronics would not exist right now. We need cars for transportation to get from Point A to Point B, and we use our phones and laptops for communication and entertainment.
Art is the form of human activities in creating visual, auditory or performing artifacts. Without art, life wouldn't be very pleasurable. People want to express themselves, and people want to see beauty. Art also helps historians tell about the past.
Hope this helped!
