Answer:
I think you're referring to the Metaphase...
Explanation:
During Cell Division (or, rather before!) the DNA needs to be replicated. This normally is done by DNA Polymerase, and results in two identical double strands (the "Sister Chromatids".
These chromatids are held together at the Centromere, which will be the heart of the "X"-shape. After that the DNA is packed into Chromosomes by winding it around proteins called Histones. If I remember correctly there are 5 different Histones.
This "Zipping Up" makes the chromosomes more visible.
As the two sister chromatids are still connected, the result is the X-shaped Metaphase Chromosome....
A circle is to round as an oval is to elliptical/egglike.
The best answer is B.
The endosymbiotic theory states that mitochondria and chloroplasts have striking similarities to bacterial cells:
1. they have their own DNA, which is separate from the DNA found in the nucleus of the cell.
2. Both organelles use their DNA for to produce many proteins and enzymes required for function.
3. They are both surrounded by a double membrane.
4. They reproduce just the way bacteria do, replicating their own DNA and directing their own division.
DNA microarrays allow the rapid and simultaneously SCREENING of many thousands of genes.
Varieties of plants in which self-fertilization produces offspring that are identical to the parents are referred to as true-breeding. In this process the parents will pass down specific phenotypic trait of their offspring. True bred organisms will have pure genotype (genetic make up of an organism) and will therefore produce certain phenotype.
