<span>it can form four covalent bonds it forms very strong bonds
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Answer:B.The signal is either similar in structure to a ligand used by eukaryotes, or this signaling pathway is utilized by both prokaryotes and eukaryotes.
Explanation: Eucaryotic cell is a cell whose Nucleus is clearly defined and confined within a membrane.
Procaryotic cell is a cell which does not have a clearly defined Nucleus.
Signals are stimuli which can be felt by an organism, specific organismal have its own kinds of signals which it can respond to,but some times signals with specific features can create response in two or more type or species of organisms. What happened in the lab is a case where a partial signal can be sensed by both procaryotes and eucaryotes because it has either a similar structure or its pathway can be used by either Eucaryotic cells and procaryotic cells.
Few advancements in scientific knowledge were made.
Scientists discovered new evidence to support their theories.
Scientists used observations and mathematical data to solve problems in new ways.
<u>Explanation:</u>
At first the Ptolemaic model suggested that the earth was the centre of the solar system around which the sun, moon and other planets revolved. This Copernican revolutionised by finding Sun in the centre of the solar system around which the earth and the other planets revolved. After his discovery the earth was just given a status of yet another planet.
The scientists who were researching on this made few advancements using their scientific knowledge and hence found new evidences to support their theory. Scientists then researched conducted experiments using mathematical calculations to solve their problems.