Answer:
d. all of the above
Explanation:
all the above answers are correct about Science
<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:
Yeah, so basically the image is showing restriction enzymes. The job of restriction enzymes is mainly involved in research when scientists use them for cloning human genes. But that's besides the point...
Main thing you have to understand is that restriction enzymes cut at very specific places along DNA sequences. If you look at the restriction enzyme Rsa 1, you can notice that it cuts only between a thymine nucleotide base and an adenine nucleotide base. Next, if ya look at Sty 1 (be careful b/c W can represent adenine or thymine), it cuts only between two directly adjacent cytosine nucleotide bases!
SO.... if we go to Rsa 1, we can find the answers by dividing up the sequences between the pattern we saw in the gray box. It only cuts between adenine and thymine bases. Based on that, we can find the number of fragments created, and the segment lengths (basically just like how many nucleotide bases are in each strand). Hope ya found this helpful!
