His mother and his father are both carriers of the recessive gene.
Answer:
No. They will need to repeat their experiment several times, since the weather and times were different both days.
Explanation:
When a scientific experiment is conducted, one independent variable shall be changed in each experiment at a time so that the results of the experiment are authentic and we can easily determine which independent variable caused a change in the dependent variable.
If more than one independent variable is changed in the same experiment, then it will be difficult to interpret that which variable caused the change.
<u><em>Similarly, Maria and her brother need to repeat their experiment several times with just changing one variable at a time. </em></u>
The exercise tells you to complete the table showing different cases of mutation in different parts of the operon.
First, what is an operon?An operon is a genetic unit of coordinated expression. It comprises a group of adjacent structural genes encoding the enzymes of the same metabolic pathway, as well as the regulatory sequences affecting the transcription of these structural genes (like operon lactose or tryptophan). It is composed by:
Structural genes/cistrons: code for the enzymes participating in the same metabolic pathway, they are co-transcribed into a single polycistronic mRNA.
• Promoter common to all structural genes: this is the binding site of RNA polymerase.
• The operator: it is a regulatory sequence, it is the site of binding of the protein of the regulation, it controls the transcription of the gene downstream.
• The regulatory gene: located upstream of the operon promoter, it encodes regulatory proteins capable of binding on the operator. He owns his own promoter.
*If a mutation touch one of the genes that the operon code for, this gene will be not functional
*If a mutation touches the operator none of the enzymes will be synthesized
*If a mutation touches a repressor (a molecule which inhibits the expression of the operon genes by binding specifically to the DNA at the operator level).
Based on this, the right answers are:
Mutant 1 ==> gene A
Mutant 2 ==> repressor
Mutant 3 ==> gene B
Mutant 4 ==> promoter
Earth's tilt on its axis affects the way heat is distributed on Earth's surface.
The Earth orbits the sun every 365 ¼ days. The Earth is tilted 23.5 degrees on its axis, which affects the distribution of the sun’s energy across the surface of the planet. More tilt means more severe seasons, that is warmer summers and colder winters where as less tilt means less severe seasons, that is cooler summers and milder winters.
Find out more on earth tilt at: brainly.com/question/818630