Answer:
1. Cervical
2. Lumbar
Explanation:
Spinal enlargements are the conspicuous regions in the spinal cord from where spinal nerves to and from limbs exit and enter respectively. Cervical enlargement is also called the superior enlargement. It starts from C4, the fourth cervical vertebra and extends to T1, the first thoracic vertebra. Cervical enlargement is the site from there the nerve that supplies to and come from the upper limbs arise.
Another enlargement is the lumbar enlargement. It is also called inferior enlargement or lumbosacral enlargement and extends from the ninth to the twelfth thoracic vertebra. It is the site from where the nerves to and from the lower limbs arise.
Answer:
aquatic and terrestrial habitat.
example of an animal in aquatic is fish and an example of a terrestrial animal is human
This would be a relation ship of either mutualism or symbiosis
Answer:
C. "Because you have had one child with Tay-Sachs, you must each carry the allele. Any child you have has a 25% chance of having the disease
Explanation:
Tay-Sachs disease is an autosomal recessive disorder that means a child will acquire the phenotype or we can say disease only when both the alleles which cause disease are present in the child.
Here, in this condition neither parent has Tay-Sachs but they gave birth to a child who is suffering from the disease then it simply means that both the parents are carrier of this disease i.e. they both are heterozygous.
The cross and probability of healthy and diseased child is shown as under:
Mother Father
Parents Tt Tt
/ | | \
Off-springs TT Tt Tt tt
<u>Out of these 4 probable off-springs only 3 with genotype TT, Tt & Tt will be healthy while the 1 with genotype tt will be diseased.</u><u> </u><u>So, the probability of diseased child is 1/4 which is 25%. </u>
Also, the birth of children is an independent event so if one child has already been born with this disease then it doesn't mean that the next 3 children will be healthy for sure i.e. birth of first child cannot influence the next child. In short we can also say that in the next birth, there is still 25% chance of the child being born with this disease because previous birth has nothing to do with next birth.
Answer:
C. many mosquitoes today are descendants of mosquitoes with insecticide-resistant characteristics
Explanation:
When insecticides were first sold, they where highly effective in killing mosquitoes but few mosquitoes will definitely survived. If these mosquitoes that survived mate together, they will produce hybrid offspring that possess characteristics that are insecticide-resistant. The more insecticide-resistant mosquitoes that breed together in subsequent generations, the more permanent mutant hybrid offspring will be produced which will eventually make them to become resistant to the use of insecticides over them.
