Answer:
<h2>False</h2>
Explanation:
Natural killer cells (NK cells) are a type of lymphocyte and also a component of innate immune system. NK cells play various functions in immune system and they play a major role in the host-rejection in virally infected cells.
NK cells are activated in response to interferons and also by various other responses. NK cells work to by secreting IFNγ and TNFα. Natural killer cells play a very important role in early host defense against viruses.
Answer:
There is no enough data on Earth's temperature before life appeared.
Explanation:
The correct answer is:
It occurs when part of a chromosome breaks off and attaches to another chromosome.
It results in the duplication of these genes on the same chromosome.
Fragile X syndrome can occur where a person would have 700 insertion repeats.
Difficulties include delay in crawling or walking, hyperactive or impulsive behavior, mental retrdation, flat feet, flexible joints, and large body size.
Hope it helps!
Answer:
Answer is explained below;
Explanation:
Mercury is a liquid metal that is released into the environment by both natural processes such as volcanic activity, weathering of rocks, etc and human activities such as waste materials from factories. The mercury that reaches the ocean and other water sources is converted into methylmercury by bacteria. Methylmercury is a neurotoxin that interferes with the nervous system and is easily absorbed by the human body.
The methylmercury is taken up by planktons. Small fishes consume large quantities of plankton. Tilapia is a small, short-lived freshwater fish. The methylmercury level in tilapia is lower than that of other fish. When large, long-living predatory fishes such as tuna, shark, king mackerel, swordfish, etc consume many smaller fish with low mercury levels, this causes accumulation of methylmercury at extremely high levels in their tissues over time i.e., the amount of mercury in such bigger fish biomagnifies.
So large, long-lived predators like swordfish and shark often have the highest methyl mercury levels than a small, short-lived tilapia.
