Answer: Sieve tubes and cytoplasm.
Explanation:
Answer:
Natural selection is least likely to occur in this population if:
- The resources are continuously available
For a species to survive in an area, it is essential that the place has enough resources like nutrients, space, water etc. If these resources are available then there will be less chances of competition which will lead to lesser chances of natural selection.
- The number of of death rates is equal to the number of of birth rates
In an balanced ecosystem, the number of birth rates is equal to the number of death rates for a population. If the number of death rates is lesser to the number of birth rates then the competition for resources will lead to natural selection.
This information is not enough to tell which of the traits-blood group A or O is dominant.
It is known that blood groups A and B are codominant, which means both will express if found together in a heterozygote. However, blood group O is recessive. But from this information, you can conclude that blood group O is dominant. Why is that so?
Let's imagine that father's genotype is AA and mothers' genotype OO and cross them:
Parents: AA x OO
Offspring: AO AO AO AO
Since we have information that daughter has blood group O, we can conclude that O is dominant over A and mask it. This is not true! In this case, the daughter will have blood group A.
Mother's genotype surely is OO (because O allele is recessive, so to express a recessive trait both alleles must be recessive). But, the father cannot be AA, because it must give O allele to the daughter so she can have genotype OO and blood group O. So, the father's genotype is AO. Let's take a look at that crossing:
Parents: AO x OO
Offspring: AO AO OO OO
Thus, in this case, daughter can have genotype OO and blood group O.
