Phylum Cnidarian: Jellyfish
Phylum Arthropod: Lobster
Phylum Echinoderm: Starfish
- <span>Echinoderms are characterized by </span>radial symmetry<span>, several arms radiating from a central body </span>
I believe the answer is B - point source comes from a specific site, non-point comes from many sources
A. Gametes are the male and female reproductive cells (Sperm and Egg) While body cells make up all organs, Stem cells are undifferentiated cells in a multicellular organism and somatic cells are any cells in the body other than reproductive cells.
Intramembranous ossification is the formation of bone from fibrous membranes. Intramembraneous ossification is the embryonic development of flat bones from an embryonic tissue called the mesesnchyme. The bones formed through the intramembranous ossification includes the flat bones of the face, most of the cranial bones, and a good deal of the clavicles. Other bones at the base of the skull and the long bones are formed via endochondral ossifiaction.
Answer:
a. repressor
b. regulator
c. operator
Explanation:
All constituent genes of an operon are transcribed in a coordinated manner, such as polycistronic mRNA, that is, multigenic, which is sequentially translated into proteins by ribosomes. The initiation of transcription can be regulated positively or negatively. The genes under negative control are constantly expressed unless they are "disconnected" by a repressor protein that will prevent gene expression by binding to a specific DNA sequence called operator, preventing RNA polymerase from initiating transcription in the promoter.
Those genes whose expression is under positive control will not be transcribed unless an activating protein is present which binds to a specific DNA sequence and helps RNA polymerase in the initial steps of transcription.