Answer:
Cross overs can lead to formation of chromosome pairs that have no mutant allele.
Explanation:
Cross overs can lead to formation of chromosome pairs that have no mutant allele.
For example -
Suppose "X" is a mutant allele and "x" is a mutant free allele.
Now when two homologous chromosomes contains a single mutant allele in different parts of the chromosome are crossed the following offspring are produced
X x
X XX Xx
x Xx xx
"xx" is a mutant free genotype.
Thus, crossing over can create a single mutation-free chromosome
I suggest you to provide some options, as it's quite difficult to answer your question. Here is your answer: A long bone is covered externally with a sheath called the
periosteum, whereas the marrow cavity is lined with the <span>
endosteum</span>
. I've attached the illustration to make it clear for you
Oh I know this, It narrows down its characteristics here is an example:
The first step in the key will be organized the following way:
1. a. wings covered by an exoskeleton
b. wings not covered by an exoskeleton
Next, the statements need to lead the observer to the next step to narrow the identification further:
1. a. wings covered by an exoskeleton go to step 2
b. wings not covered by an exoskeleton .go to step 3
Step 2 needs to consist of a pair of statements that will allow for the identification of the ladybug and the grasshopper:
2. a. body has a round shape .ladybug
b<span>. body has an elongated shape .grasshopper</span>