<span>Human weight at the time of birth is influenced by stabilizing selection. Stabilizing selection, also known as negative selection, purifying selection or normalizing selection, is a type of natural selection in which genetic diversity decays according to a particular value of the character. This is the most common mechanism of action of natural selection.</span>
Wenger used the shapes of the continents as puzzle's pieces and how they fit perfectly together.
In gram positive bacteria have a peptidoglycan layer outside of the cell wall. Gram negative bacteria have peptidoglycan between membranes.
The natural penicillin have activity against non beta lactamase producing gram - positive cocci, which includes such as - viridans streptococci, anaerobic streptococcus. Penicillin work indirectly bursting bacteria cell walls. It kills bacteria through binding of that betalactum ring.
Gram positive bacteria have a much thicker layer of peptidoglycan and lack of the protection of an outer membrane. This class , penicillin was first antibiotic to be used widely and prevents the final cross linking step. There are some more classes of penicillin like- natural , penicillin-stable, aminopenicillins and extended-spectrum penicillin.
To learn more about gram positive bacteria here
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This might have been the cause of not being exposed to this specific pollen during his years in Chicago. Allergic reactions can develop when the stimuli presented even when its not contagious causes the immune system to trigger and act in a defensive stance. This delayed effect may have been the cause of the sudden expression of the immune system.
The answer is D) 1/2.
Let's imagine that two genes of the genotype can be analysed separately.
Black fur is determined by dominant allele B. In this case, parents Bb and BB will give offspring with only brown fur:
Parents: Bb x BB
Offspring: BB BB Bb Bb
Both homozygous (BB) and heterozygous (Bb) offspring will have black fur.
On the other hand, long tails are determined by recessive allele t. Parents Tt and tt will have 50% offspring with short tail and 50% offspring with long tail:
Parents: Tt x tt
Offspring: Tt Tt tt tt
Heterozygous offspring (Tt) will have short tail, and homozygous offspring (tt) will have a long tail.
So, the offspring will definitely have black fur and will not affect the fraction of the offspring with black fur and long tails from the cross of <span>BbTt × BBtt. But, </span>there will be 2 out of 4 offspring with short tails which is 50% or 1/2.
