Answer:B
Explanation:provitamin A is preformed vitamin A .. The best source of these are animal sources than plant sources.. Best sources include diary foods,, meat and fish.
English: Density is MassUnit Volume; relative density is the density compared to a reference substance (usually water) under standard conditions.
Nepali: घनत्व मास एकाई भोल्यूम हो; सापेक्ष घनत्व मानक अवस्था अन्तर्गत सन्दर्भ पदार्थ (सामान्यतया पानी) को तुलनामा घनत्व हो।
B) Geothermal energy
It is heat within the earth
