Left auricle and left ventricle
Answer:
A
Explanation:
1 half-life = .4 kg = 15 years
2 half-life = .2 kg = 30 years
3 half-life = .1 kg = 45 years
4 half-life = .05 kg = 60 years
<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.
Answer:
Activated
Explanation:
In the presence of lactose, and in the absence of glucose, lactose will bind to a protein called a "repressor," deactivating it. Through this, RNA polymerase has a free way to synthesize the mRNA that will give enzymes for lactose degradation.
