Estimated mean requirement and safe level of intake for vitamin A, in Retinol Equivalents (RE) (1 RE = 1 mcg. of retinol or 6 mcg. of beta-carotene):
- Adolescents, 10–18 years: 330–400 (mcg RE/day, mean requirement), 600 (mcg RE/day, recommended safe intake)
- Adult females, 19–65 years: 270 (mcg RE/day, mean requirement), 500 (mcg RE/day, recommended safe intake)
- Adult females, 65+ years: 300 (mcg RE/day, mean requirement), 600 (mcg RE/day, recommended safe intake)
- Males: 300 (mcg RE/day, mean requirement), 600 (mcg RE/day, recommended safe intake)
Food sources, examples (RE per 100 grams).
Fresh fruits and raw and cooked fruit vegetables:
- Mango - 523
- Apricots - 260 (dry - 730)
- Cantaloup 322
- Squash, cooked 714
- Red pepper, raw - 580
Root (tubers) and green vegetables, flowers:
- Carrots, raw - 2574
- Sweet potato, cooked - 2180
- Dandelion, raw - 1400
- Spinach, raw - 674
- Spirulina - 28333
- Nori - 4895
A sharp distinction between humans and “animals” is essential if we are to bend them to our will, make them work for us, wear them, eat them–without any disquieting tinges of guilt or regret. It is unseemly of us, who often behave so unfeeling toward other animals, to contend that only humans can suffer. The behavior of other animals renders such pretensions specious. They are just too much like us.
Archaea and bacteria (eubacteria) are single-celled organisms that do not have a nucleus or organelles. Archaea have a distinct evolutionary history and biochemistry compared with bacteria.
Archaea - a domain of single-celled microorganisms. These microbes are prokaryotes. Archaea can survive in extreme and harsh environments like hot springs, salt lakes, marshlands, oceans, gut of ruminants and humans.
Bacteria - a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals. Eubacteria are ubiquitous and are found in soil, hot springs, radioactive waste water, Earth's crust, organic matter, bodies of plants and animals, etc.