Physician recommends radiation therapy because radiation therapy helps in preventing cellular growth. It uses high-energy radiation to shrink tumor or kill cancer cells. It may be used to cure or to control malignancy when the tumor can no longer be removed or when lymph node involvement is present; also, it can be used prophylactically to prevent spread. Radiation therapy kills cancer cells by damaging their DNA which is the molecules inside cells that carry genetic information and pass it from generation to generation. Radiation therapy can either damage DNA directly or create charged particles within the cells that can in turn damage the DNA. Cancer cells whose DNA is damaged beyond repair stop dividing or die and when these cells die, they are eliminated by the body through natural process.
<u>Answer:</u> "Chemical fossils"evidence supports the notion that sponges are some of the earliest known multicellular animals.
<u>Explanation:</u>
Sponges are multicellular animals, may belong to Ediacarian period likely to be 80 million years ago or earlier. They catered through a complex system of internal channels, by moving seawater.
Sponges are soft-bodied and very rarely protected as fossils, therefore finding evidence of existence is giant task. The key of their existence came to know from abnormal chemicals which is a steroids of a particular type generated sufficiently by them but virtually never by ordinary organisms.
Analysis of long strata sequence found in Oman and researchers have been able to extract these "chemical fossils" from samples spanning tens of millions of years — before, during and after the Ediacarian period.This gave clear evidence that sponges had to have evolved long before the great variety of multicellular organisms proliferated at the dawn of that time.
B. The nervous system collects and responds to information about the external and internal environment.
The right answer for the question that is being asked and shown above is that:
The density of a certain object can be solved using two parameters: The mass and the volume.
Density = mass / volume.
So, from the given question, we are lacking on what the volume is.
