That would be 29 because if u look at all the other years at the end of all the years the number is only a few numbers up from the first number.
The X can possibly be the sex chromosome. Like for human female we have the XX chromosomes and when the allele is on the X chromosome we write as X with a R as the superscript on top right.
Https://undsci.berkeley.edu/lessons/heating_cooling.html (This should help you)
Renewable energy sources include hydropower<span>, wood biomass (used to generate heat and electricity), alternative biomass fuels (such as ethanol and </span>biodiesel<span>), waste, </span>geothermal<span>, wind, and </span>solar<span>.</span>
