Answer:
True
Explanation:
In phase-contrast objective and a phase contrast optical systems is equipped with Light microscope .
Phase contrast microscope is used to differentiate unstained structures in a cell that differ in refractive indices and thickness. Thus it is usefull for examining living unstained organisms.
Light that passed through materials of different refractive index and/or thickness will undergo a change in Phase. The difference in phase or wave front irregularities cause variation in brightness of the structures.
Hoping this might help!!!
Two genes, BRCA1, located on chromosome 17q21 (5,6), and BRCA2, located on 13q12-13 (7–9), have been shown to predispose to familial breast cancer.
The given question is incomplete as the genotype of the parents is not given, so the answer is providing in the followings case:
1. dominant parent and recessive parent
2. heterozygous parents
Answer:
1. dominant parent and recessive parent:
dominant parents can be represented by LL and recessive parent is represented by ll, so the gametes would be L, L and l, l.
so,
L L
l Ll Ll
l Ll Ll
so there are all offspring in heterozygous condition as we known one or two dominant allele masks the recessive allele for the trait so 100% offspring can fold their tongue.
2. heterozygous parents
In this case, parents have Ll genotype and gametes would be L and l for each parent so,
L l
L LL Ll
l Ll ll
In this case, one is pure dominant and two heterozygous whereas only one is recessive so, the phenotype of offspring that cant fol the tongue would be:
3/4 = 75%
The consequence of over fertilization can include eutrophication in nearby waters.
hope it helps u.......
Answer: D. a genetic bottleneck
Explanation:
A genetic bottleneck also known as a population bottleneck is one that describes a sharp reduction in the size of a population caused by environmental events like in the above or caused by human activities.
