Answer:
No, CREs usually don't account for differences in gene expression levels.
Explanation:
<em>Cis</em>-regulatory elements (CREs) are non-coding DNA regions that regulate adjacent gene <em>transcription</em>. They usually do it by binding to transcription factors. They are in charge of influencing the rate of which transcription occurs, and less with how much a gene is expressed. On the other hand, trans-regulatory elements are DNA sequences that encode for upstream regulators that can modify or regulate <em>gene expression levels</em>.
Therefore, cis elements are not really in charge of expression levels, mostly transcription rates of single genes, rather. Trans elements are more involved in expression levels.
Sand dunes or desert pavement
First, a complete digestive system means that the digestive tract has a beginning or the oral end and the opposite end or the aboral end. This is found in more complex animals starting from roundworms (flatworms have an incomplete digestive tract). A closed circulatory system is found in animals more recent than mollusks. The presence of the coelom makes it more evolved than the flatworms.
Specifically, a small animal with a segmented body, short stiff appendages, and soft skin with the above characteristics point out to the phylum Annelida or annelids.
Answer:
be scared but don't. act tough.
