The attainment of high efficiency in blue LEDs was quickly followed by the development of the first white LED. In this device a Y
3Al
5O
12:Ce (known as "YAG") phosphor coating on the emitter absorbs some of the blue emission and produces yellow light through fluorescence. The combination of that yellow with remaining blue light appears white to the eye. However using different phosphors (fluorescent materials) it also became possible to instead produce green and red light through fluorescence. The resulting mixture of red, green and blue is not only perceived by humans as white light but is superior for illumination in terms of color rendering, whereas one cannot appreciate the color of red or green objects illuminated only by the yellow (and remaining blue) wavelengths from the YAG phosphor.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What LED quickly followed the red LEDs?
Ah, so.. unanswerable

Accounts of the use of leeches for the medically dubious practise of blood-letting have come from China around 30 AD, India around 200 AD, ancient Rome around 50 AD and later throughout Europe. In the 19th century medical demand for leeches was so high that some areas' stocks were exhausted and other regions imposed restrictions or bans on exports, and Hirudo medicinalis is treated as an endangered species by both IUCN and CITES. More recently leeches have been used to assist in microsurgery, and their saliva has provided anti-inflammatory compounds and several important anticoagulants, one of which also prevents tumors from spreading.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): Where did leeches begin being used for blood transfusions?
Ah, so.. unanswerable

In the Southern Russian dialects, instances of unstressed /e/ and /a/ following palatalized consonants and preceding a stressed syllable are not reduced to [ɪ] (as occurs in the Moscow dialect), being instead pronounced [a] in such positions (e.g. несли is pronounced [nʲaˈslʲi], not [nʲɪsˈlʲi]) – this is called yakanye/яканье. Consonants include a fricative /ɣ/, a semivowel /w~u̯/ and /x~xv~xw/, whereas the Standard and Northern dialects have the consonants /ɡ/, /v/, and final /l/ and /f/, respectively. The morphology features a palatalized final /tʲ/ in 3rd person forms of verbs (this is unpalatalized in the Standard and Northern dialects). Some of these features such as akanye/yakanye, a debuccalized or lenited /ɡ/, a semivowel /w~u̯/ and palatalized final /tʲ/ in 3rd person forms of verbs are also present in modern Belarusian and some dialects of Ukrainian (Eastern Polesian), indicating a linguistic continuum.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What does Southern Russian have a linguistic continuum with?
Ah, so..
modern Belarusian and some dialects of Ukrainian (Eastern Polesian)