<h2>Answer</h2>
The plasma membrane is made up of a phospholipid bilayer, with the <u>Hydrophilic</u><u> </u><u>Heads</u> of the phospholipids <u>sticking out toward the interior and exterior of the cell</u>.
- <u>The hydrophilic polar head of the phospholipid is attracted to water, while the hydrophobic tails are excluded by water.</u>
Correct me if I'm wrong !!
<h3 /><h3 /><h3>#CarryOnLearning</h3>

Answer:
Sigma factors bind to the promoter region of a particular gene and facilitating the binding of RNA Polymerase to the promoter region (formation of the RNA polymerase holoenzyme complex) in order initiate transcription of the gene.
Put simply - Helps RNA Polymerase do it's job.
Answer:
Dr. Stott's belief about that the 9-year-olds will advance in knowledge based on instructions is based on the theory of cognitive development, proposed by Lev Vygotsky.
Explanation:
Theory of cognitive development -also called the socio-cultural theory of cognition- was put forward by the Russian-Jewish psychologist Lev Vygotsky, in which he expresses the influence of the socio-cultural environment on the learning process.
<u>For Vygotsky, children possess innate basic skills, such as attention, sensation, memory and perception, which develop over time</u>.
The process of cognitive development implies that the development of each child's basic skills requires the guidance of an adult, since -although there are skills that he does not understand or has not developed- he can learn them with the appropriate guidance and instructions.
<u>Answer:</u>
<em>Atomic clock doesn’t contain decaying isotopes.
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<u>Explanation:</u><u>
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It is the <em>decay of radioactive elements</em> that emit radiations and most of these are harmful to life. But atomic clock doesn’t work on the principle of atomic decay. There is no atomic decay occurring in an atomic clock and thus there is no <em>harmful radiation being emitted from the atomic clock</em>.
Caesium atomic clocks, rubidium atomic clocks etc are some of the atomic clocks. The working principle of atomic clocks is the transition of atoms between various energy levels.
The <em>frequency of Electromagnetic signal</em> emitted during transition of atoms to higher energy levels is the basic factor that determines the working and <em>efficiency of an atomic clock.
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