Answer:
Answer is 2. Fibroblasts fail to divide.
Explanation:
Tissue culture experiment is the experiment where tissues are grown in an artificial medium. This involves the use of growth medium such as agar or broth. This process help to produce needed tissues in a short period of time.
Fibroblasts are cells which are found in the collective tissues, and they produce collagen. The collagen produced by the Fibroblasts play important role in tissue repair. Fibroblasts are regarded as the main cells in the connective tissue.
Note that, PDGF, which is Platelet -derived growth factor in full, is a growth factor regulating cell growth and it's division.
<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.
Answer:
The various stages of development in children are reached at a unique time and rate for every child. But there are a number of common key categories to consider when looking at your child’s early health and development. Explanation:
In infancy, toddlerhood, and early childhood, the body’s physical development is rapid (Figure 1). On average, newborns weigh between 5 and 10 pounds, and a newborn’s weight typically doubles in six months and triples in one year. By 2 years old the weight will have quadrupled, so we can expect that a 2 year old should weigh between 20 and 40 pounds.
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They r able to dig down by eating soil, then eliminating them through the anus
their digestive system is able to break down decomposing plants, that is a common source of organic materials in the soil
