Answer:
To observe the cheek cell,
-
Take a tooth pick use its blunt side to scrap inside the mouth.
- You will see some deposition on the blunt side of tooth pick, make a smear on the clean slide in the center using that tooth pick.
- Add a drop of methylene blue solution and place a coverslip, make sure that bubbles are avoided i.e. coverslip should be placed in the inclined manner.
- Remove the excess solution and observe it under the microscope first under 4X and then under 10X.
Observation:
- The cells observed are squamous epithelial cells. The small blue dots seen inside will be the bacteria from our teeth and mouth.
More than 4.2 million Americans aged 40 years and older are either legally blind (having best-corrected visual acuity of 6/60 or worse (=20/200) in the better-seeing eye) or are with low vision (having best-corrected visual acuity less than 6/12 (<20/40) in the better-seeing eye, excluding those who were categorized as being blind).
The leading causes of blindness and low vision in the United States are primarily age-related eye diseases such as age-related macular degeneration, cataract, diabetic retinopathy, and glaucoma. Other common eye disorders include amblyopia and strabismus.
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Refractive Errors
Refractive Errors
Refractive errors are the most frequent eye problems in the United States. Refractive errors include myopia (near-sightedness), hyperopia (farsightedness), astigmatism (distorted vision at all distances), and presbyopia that occurs between age 40–50 years (loss of the ability to focus up close, inability to read letters of the phone book, need to hold newspaper farther away to see clearly) can be corrected by eyeglasses, contact lenses, or in some cases surgery. The National Eye Institute states that proper refractive correction could improve vision among 150 million Americans.
A contractile vacuole regulates water in some protozoans.
Answer:
iAiA and iBiB
Explanation:
Blood type in humans is controlled by a gene with three alleles namely: iA, iB, and i. Alleles iA and iB are dominant over allele 'i' but codominant. The following are the allelic combinations of the genotype and the resulting blood types:
iAiA or iAi - type A
iBiB or iBi - type B
iAiB - type AB
ii - type O
According to this question, one parent has type A blood and the other has type B. If all the offsprings of these parents have blood type AB, this means that the parents must have a genotype of iAiA and iBiB respectively.