Answer: It is important that cells have a "control system" because without it cells would either divide too fast or cause tumors to grow (cancer), or divide too slow and not be able to perform their cellular functions which is why the cells are controlled.
For building protein the first step should be DNA that makes how protein should be so the answer is C :))
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<h2><u>
Full Question:</u></h2>
In the family tree below, people with the recessive trait of attached earlobes are shaded gray.
What must be true about the person labeled "A"?
A. It is a male with at least one dominant allele.
B. It is a male with two dominant alleles.
C. It is a female with at least one dominant allele.
D. It is a female with two dominant alleles.
<h2><u>Answer:</u></h2>
Its a male with atleast one dominant allele.
Option A.
<h3><u>Explanation:</u></h3>
The gene for the attached earlobe is recessive while the gene for the free earlobes is dominant. In the phylogenetic tree, we can see that both the father and mother aren't having attached earlobes. So both of them are having atleast one dominant allele which makes them have free earlobe.
In the F1 offsprings, one of the female and a male is having free earlobes. So both of them have atleast one dominant allele. The 2nd female is having an attached earlobe. So both the recessive allele have come form one parent each. So both of them are heterozygous.
Thus, the male marked as A atleast have one dominant allele. He can be a homozygous dominant, but the probability is 25%.
The vascular cambium produces secondary phloem and xylem tissue.
Vascular cambium, a plant tissue located between the xylem and the phloem in the stem of a vascular plant. It is also the source of both secondary xylem growth and the secondary phloem growth. Vascular cambium is usually found on dicots and gymnosperms not on monocots which usually lack secondary growth. It does not transport water, dissolved food or minerals by plants.Vascular cambia are cylinders of unspecialized meristem cells which divide to make new cells which specialize to form secondary vascular tissues.<span> </span>