i) The Mandragora Helix, also called the Mandragora constellation was a Helix Intelligence that appeared in the 1976 serial The Masque of Mandragora. A spiral of energy with a controlling intelligence, Mandragora existed as its own domain in "unchartered regions of the Time Vortex." Helix Intelligences were sentient astral forces that resided in/existed as spirals of pure energy. The only known Helix was the Mandragora Helix, though one account claimed there were multiple Intelligences within Mandragora.

... Speech Sample taken from 'Genesis Of The Daleks' by Terry Nation broadcast between 8th March 1975 and 12th April 1975 starring Tom Baker ...

ii) Helixes possessed archetypal memories, able to absorb the emotions, consciousness, and genetic cells of others. They had great manipulative power that could recreate stone structures or destroy beings, making their skin appear blue and crystallised. Their energies could be spread out, but this would exhaust their being, and their energy could become grounded by metal, rendering them harmless.

The distress signal receiver was supposedly a component in the Doctor's TARDIS that let the Doctor pick up distress signals from anyone, anywhere. He always answered them despite not knowing who had sent them.

iii) The Tenth Doctor explained that Mandragora originated during the Dark Times, commenting that it should never have been released from its dimension, implying the Helixes originated from outside the universe, since Mandragora was "old even when this universe was born."

...The Doctor Who theme music is a piece of music written by Australian composer Ron Grainer and realised by Delia Derbyshire at the BBC Radiophonic Workshop. Created in 1963, it was one of the first electronic music signature tunes for television. Although numerous arrangements of the theme have been used on television, the main melody has remained the same. The theme was originally written and arranged in the key of E minor, utilising the phrygian mode. The original 1963 recording of the Doctor Who theme music is widely regarded as a significant and innovative piece of electronic music, recorded well before the availability of commercial synthesisers. Delia Derbyshire (assisted by Dick Mills) of the BBC Radiophonic Workshop used musique concrète techniques to realise a score written by composer Ron Grainer. Each note was individually created by cutting, splicing, speeding up and slowing down segments of analogue tape containing recordings of a single plucked string, white noise, and the simple harmonic waveforms of test-tone oscillators which were used for calibrating equipment and rooms, not creating music. The main, pulsing bassline rhythm was created from a recording of a single plucked string, played over and over again in different patterns created by splicing copies of the sound, with different pitches and notes achieved by playing the sample in different speeds. The swooping melody and lower bassline layer were created by manually adjusting the pitch of oscillator banks to a carefully timed pattern. The non-swooping parts of the melody were created by playing a keyboard attached to the oscillator banks. The rhythmic hissing sounds, "bubbles" and "clouds", were created by cutting tape recordings of filtered white noise. Once each sound had been created, it was modified. Some sounds were created at all the required pitches direct from the oscillators, others had to be re-pitched later by adjusting the tape playback speed and re-recording the sound onto another tape player. This process continued until every sound was available at all the required pitches. To create dynamics, the notes were re-recorded at slightly different levels. Each individual note was then trimmed to length by cutting the tape, and stuck together in the right order. This was done for each "line" in the music – the main plucked bass, the bass slides (an organ-like tone emphasising the grace notes), the hisses, the swoops, the melody, a second melody line (a high organ-like tone used for emphasis), and the bubbles and clouds. Most of these individual bits of tape making up lines of music, complete with edits every inch, still survive...

...This done, the music had to be "mixed". There were no multitrack tape machines, so rudimentary multitrack techniques were invented: each length of tape was placed on a separate tape machine and all the machines were started simultaneously and the outputs mixed together. If the machines didn't stay in sync, they started again, maybe cutting tapes slightly here and there to help. In fact, a number of "submixes" were made to ease the process – a combined bass track, combined melody track, bubble track, and hisses. Grainer was amazed at the resulting piece of music and when he heard it, famously asked, "Did I write that?" Derbyshire modestly replied, "Most of it." However the BBC, who wanted to keep members of the Workshop anonymous, prevented Grainer from getting Derbyshire a co-composer credit and a share of the royalties. The theme can be divided into several distinctive parts. A rhythmic bass line opens and underlies the theme throughout, followed by a rising and falling set of notes that forms the main melody which is repeated several times. The bridge, also known as the "middle eight", is an uplifting interlude in a major key that usually features in the closing credits or the full version of the theme. During the early years of the series the middle eight was also often heard during the opening credits (most notably in the first episode, An Unearthly Child).