Answer:
Until recently, most neuroscientists thought we were born with all the neurons we were ever going to have. As children we might produce some new neurons to help build the pathways - called neural circuits - that act as information highways between different areas of the brain. But scientists believed that once a neural circuit was in place, adding any new neurons would disrupt the flow of information and disable the brain’s communication system.
In 1962, scientist Joseph Altman challenged this belief when he saw evidence of neurogenesis (the birth of neurons) in a region of the adult rat brain called the hippocampus. He later reported that newborn neurons migrated from their birthplace in the hippocampus to other parts of the brain. In 1979, another scientist, Michael Kaplan, confirmed Altman’s findings in the rat brain, and in 1983 he found neural precursor cells in the forebrain of an adult monkey.
These discoveries about neurogenesis in the adult brain were surprising to other researchers who didn’t think they could be true in humans. But in the early 1980s, a scientist trying to understand how birds learn to sing suggested that neuroscientists look again at neurogenesis in the adult brain and begin to see how it might make sense. In a series of experiments, Fernando Nottebohm and his research team showed that the numbers of neurons in the forebrains of male canaries dramatically increased during the mating season. This was the same time in which the birds had to learn new songs to attract females.
Why did these bird brains add neurons at such a critical time in learning? Nottebohm believed it was because fresh neurons helped store new song patterns within the neural circuits of the forebrain, the area of the brain that controls complex behaviors. These new neurons made learning possible. If birds made new neurons to help them remember and learn, Nottebohm thought the brains of mammals might too.
Other scientists believed these findings could not apply to mammals, but Elizabeth Gould later found evidence of newborn neurons in a distinct area of the brain in monkeys, and Fred Gage and Peter Eriksson showed that the adult human brain produced new neurons in a similar area.
For some neuroscientists, neurogenesis in the adult brain is still an unproven theory. But others think the evidence offers intriguing possibilities about the role of adult-generated neurons in learning and memory.
if wrong report me
Answer:
a gradual increase in the overall temperature of the earth's atmosphere because of the greenhouse effect caused by increased levels of pollutants.
Explanation:
The question is incomplete. Th ecomplete question is as following:
All of the following protect the skin and mucous membranes from infection EXCEPT
A) multiple layers of cells.
B) tears.
C) saliva.
D) HCl.
E) the "ciliary escalator."
Answer: D) HCl.
Explanation:
- The epidermis, the outer layer of the skin provides waterproofing and serves as a barrier to infection and other laers also sustain any type of injury.
- Tears wash out foreign bodies which enter the eye. In addition, tears contain a substance called lysozyme which has an antibacterial function and works to prevent microbial invasion and infection.
- Saliva protects against infection, especially via the innate immune system. This mechanism is an important first-line protection against bacterial and viral infection
- The mucociliar escalator is within the conducting airways and is composed of mucus and cilia that transfer the mucus up and out of the lungs where it can be removed by coughing or swallowing,
Whereas HCL helps in the digestion process.
Hence, the correct option is D.
The alimentary canal includes mouth, esophagus, stomach, small intestine, and large intestine. As food passes through the alimentary canal, it is exposed to the different chemical secretions from the organs of the alimentary canal, as well as from other organs, such as liver and pancreas.
First, in the mouth, salivary glands produce saliva which <span>contains enzymes involved in the food digestions. After the food is passed to the esophagus, it produces mucus to help passage of the food. In the stomach, acid and pepsinogen, as well as mucus are produced. All of these secretions help food digestion. Small intestine also produces some digestive enzymes. Further, bile from liver and enzymes from pancreas are secreted via ducts into small intestine. Finally, large intestine secretes mucus for lubrication.</span>
You need to create a table like the one below and show that, if crossed, these two dogs would create 100% wire-haired dogs, but with smooth genotype. They will be heterozygous wire-haired, because the wire hair dominates over the smooth hair.
s s
S Ss Ss
S Ss Ss
The genotype is the genes you can't see, and phenotype is what you can see. So some traits can just be in your genotype, so you don't have them but your children can get them. If there are two different traits in your genes the dominant ones will win and will be the ones you see. There needs to be two recessive genes for that gene to win. I hope this was clear. It's a little complicated!
