<span>Positive feedback</span><span>
There are two types of feedback mechanisms
Positive feedback heightens the intensity
Negative feedback lowers the intensity
These all serve to maintain homeostasis. Homeostasis is the state where the internal and external part of the body maintains and establishes balance and equilibrium. </span>
The statement in the given question that presents a condition of the Hardy-Weinberg principle is that random mating occurs. The correct option among all the options given in the question is option "C".
There are definitely certain
conditions under which the Hardy- Weinberg principle occurs and they are when
there is no gene flow, no mutations happen, no generic drift occurs and random
mating occurs. This principle also states a very important aspect and it is
that genotype and allele frequencies will always remain constant from one
generation to another if there is absence of other evolutionary inflrnce.
<u>Answer:</u>
Recent evidence suggest that feathers evolved from scales and suggest that 'feathers and pycnofibers' could be homologous.
<u>Explanation:</u>
- One of the major difficult issue related to bird evolution is the evolution of feathers.
- Feathers are considered as the most 'complex integumentary structures' which are found in vertebrates.
- Evolutionary developmental biology suggests that the 'planar scale structure' is been modified for developing into feathers by 'splitting' to form web like structures.
- Scales and Feathers consist of 'two distinct form of keratin' so it was thought that 'each type was exclusive skin structure' but recent study suggests that they are developmental expressions of same skin structures.
