A strawberry farmer finds that, after a hard freeze, some of his strawberries are still alive. Which best explains why these stran were able to survive?
A. They have larger leaves to protect the fruit than the other strawberries.
B. They have different genetic variations that cause them to be more resistant to cold temperatures.
C. They are able to reproduce more quickly than the other strawberries.
D. The color of the strawberries is darker, and they maintain their temperature better than other strawberries.

B. They have different genetic variations that cause them to be more resistant

Explanation:

We do not know the phenotype of the strawberries and cannot tell if they have a darker color or larger leaves so that eliminates A. and D. We also do not know which strawberries produce faster or if the strawberries are even a different type than the ones the froze so that eliminates C. But what we do know is that variation is key to survival and variation means some organisms might not be able to resist certain things others can.

as in mitosis, dna replication occurs during interphase.   in meiosis, it occurs specifically in s phase of interphase 1.

an individual’s sex (i.e., whether they are a male or female) is determined by the sex chromosomes. most people have two sex chromosomes, one that is inherited from their mother and one that is inherited from their father. typically, females have two x chromosomes (xx) and males have one x chromosome and one y chromosome (xy). conditions caused by changes (“mutations”) in genes located on the x chromosome are considered x-linked.

x-linked recessive inheritance

most x-linked conditions are recessive. this means that in a person with two x chromosomes (most females), both copies of a gene (i.e., one on each x chromosome) must have a change or mutation whereas in a person with one x chromosome (most males), only one copy of a gene must have a mutation. a female with a mutation in one copy of a gene on the x chromosome is said to be a “carrier” for an x-linked condition. a male with a mutation in a gene on the x chromosome is typically affected with the condition. because females have two copies of the x chromosome and males have only one x chromosome, x-linked recessive diseases are more common among males than females. however, x-linked recessive diseases can occur in both males and females.

for x-linked recessive disorders, an unaffected carrier mother who has a mutation in a gene on the x chromosome can transmit either the x chromosome with this mutation or a “normal” x chromosome to her children. if the father is unaffected, none of her daughters will be affected and all of her daughters will be unaffected—since they will inherit at least one normal x chromosome from their father. however, each daughter will have a 50% chance of being an unaffected carrier like her mother and a 50% chance of both x chromosomes being normal.