Answer:
a. substantia nigra
b. substantia nigra (it is repeated)
Explanation:
Parkinson's disease is a neurodegenerative disease that is caused by the death of neurons that release the neurotransmitter dopamine in the <u>substantia nigra</u>, or locus niger, -a region of the brain that regulates brain circuits that give the 'orders' to initiate voluntary movements- .
The lack of this neurotransmitter leads to the occurrence of the main symptoms suffered by patients: decreased movements, muscle stiffness, postural instability and tremor. These failures are generated by the abnormal way in which neurons work in the absence of dopamine through a mechanism that is not known in depth.
It is the second most frequent neurodegenerative disease, after Alzheimer's disease, with a prevalence of 2% in people over 65 years. The characteristic symptoms of stiffness, bradykinesia and tremor are associated with losses of neurons in the substantia nigra and dopamine depletion in the striatum. There are large cytoplasmic inclusions, called Lewy bodies, which are the pathological mark of the disease and appear predominantly in neurons that contain melanin of the nigra substance. Genetic studies in a subgroup of families with Parkinson's disease with autosomal dominant inheritance found a locus on chromosome 4q-21 23 and a mutation in the gene that encodes a synaptic protein, α-synuclein.
The total distance the token moved is 12 cm.
Given : space on the board game measures 1 centimeter
5 cm (up) + 5 cm (left) + 2 cm (down) = 12 cm
Asteroid impact
Volcanic eruptions
Explanation:
Asteroid impact and volcanic eruptions are two common events that could lead to a mass extinction.
A mass extinction is an abrupt decrease in life on earth due some catastrophic event.
- The collision of a large bolide on the surface of the earth is a catastrophe in itself.
- The collision and its aftermath have destructive consequences on life.
- The force of the collision can reverberate in form of vibration throughout the earth.
- It can cause heating of the earth surface.
- Volcanic eruptions can become global phenomenon that upsets the earth balance.
Learn more:
Extinction brainly.com/question/10860460
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This change in chromosome number is the result of B. Fertilization. Both of the individual gametes from the male and female combine together to produce a zygote or developing offspring that is diploid in most cases, and possess both sets of genetic content or chromosomal information, one from each parent.
The answer to that is Answer “B”
