Answer: B) Rough endoplasmic reticulum
Explanation:
<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:
The lack of Mad1 protein can cause faster cell division.
Explanation:
The Mad1 protein is responsible for regulating the fixation of chromosomes in spindle microtubules, during cell division. With the presence of this protein, anaphase is prevented from starting while the spindle, where the chromosomes attach, is formed.
Without this protein, this check is not done and cell division occurs faster, which is one of the reasons why cell division can be accelerated.
Explanation:
Cardiac muscles straited involuntary helps to pump blood through the body.
skeletal straited voluntary helps in body movement.
smooth non straited involuntary helps food to go digestive tract.