Answer: Genetic variation describes naturally occurring genetic differences among individuals of the same species. Gene duplication, mutation, or other processes can produce new genes and alleles and increase genetic variation. New genetic variation can be created within generations in a population, so a population with rapid reproduction rates will probably have high genetic variation. And there are the reasons.
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.
Answer: C
Explanation: All of them could be correct, but I think this is the correct answer. I’m only in middle school, so if your not rushing you may as well wait for someone else.
Answer: The statement is true
Explanation:
The hypothalamus is part of the Fore-brain responsible for the secretion of hormones from the pituitary gland.
This pituitary gland situated in the hypothalamus is traditionally called the MASTER ENDOCRINE GLAND, as it influence the activities of all other glands such as thyroid gland.
Thus, the hypothalamus bearing the pituitary gland is said to be in CONTROL of the activity of the thyroid, and ALSO the master endocrine gland.
