Answer:
Today, one second is defined as “9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom”. That's a mouthful.
More than 99 percent of all species, amounting to over five billion species, that ever lived on Earth are estimated to be extinct. Estimates on the number of Earth's current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described.
Answer:
- covers and lines body surfaces
- minimal intercellular substance
- cells are densley packed together
- cells rest on basement membrane
- simple (single line of cells) and stratified (multiple layers)
- squamous (oval like shape), cuboidal (cube shape), columnar (long rectangle shape)
- vascular (tissue doesn't have its own blood supply)
Explanation:
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Answer: Negative feedback serves to reduce an excessive response and to keep a variable within the normal range. Negative feedback loops control body temperature and the blood glucose level.
Fertilizer can lead to algal bloom in aquatic ecosystems, which means that its usage may lead to oversaturation of algae in the seas and oceans. Although algae are good for these kinds of waters in limited amounts, when there are too much of them it can stifle all other life, thus having negative effects on aquatic ecosystems.
