Answer:
Option A
Explanation:
Corona is defined by the strong magnetic fields. When these strong magnetic fields confine solar atmosphere and produces violent bubble of gases then it is said to cause coronal mass ejection (CME).  
When a CME passes through the solar wind, it causes production of high velocity solar energetic particles that follow magnetic field lines and passes through the space between the Sun and the Earth. The charged particle added by CME intensifies the solar wind.  
Hence, option A is correct
 
        
             
        
        
        
Answer:
a. positive; negative
Explanation:
Transcription is the process of forming an RNA molecule from a DNA template molecule. In this process, the strands of DNA separate and one serves as a template for RNA, while the other is inactive. At the end of the transcript, the tapes that have been split back together again.
The transcription process is divided into three steps: initiation, stretching and termination
During the stretching phase, transcription chain elongation occurs. In this phase the enzyme called RNA polymerase starts to move through the DNA molecule, unwinding its helix and producing an increasingly lengthened RNA molecule. The already transcribed DNA is rewound almost immediately, recomposing its double helix. This process is called the elongation phase.
During this process, it is believed that positive supercoils  are generated ahead of the transcription bubble and  and the negative supercoils behind it.
 
        
             
        
        
        
Answer:
myofibril bulbous end of axon and skeletal muscles fibres.
Explanation:o
It represents the  chemical synapse  of the axon bulbous ends  of the motor neuron ( motor end plate) and the skeletal Muscle fibres. 
The influx of calcium ions into the bulbous ends leads to the fusion  and empty of the vesicles containing neurotransmitters into the synaptic cleft.
The Neurotransmitters binds to the receptors on the muscles membrane to allow the transmission of action potential ( PSIP or  PSEP)across the synaptic gap  to the muscles fibers  to initiate  their  contraction or relaxation.
 
        
             
        
        
        
The right answer is C) vector
In molecular biology and genetic engineering, vectors are DNA molecules that allow the propagation of sequences of interest. These are chimeric DNA molecules such as plasmids or artificial bacterial chromosomes, containing an origin of replication and one or more genetic markers. The origin of replication allows the maintenance of the vector in the target cell during generations.