The indicator dinitrophenol is an acid with a Ka of 1.1x10–4. In a 1.0x10–4-M solution, it is colorless in acid and yellow in base

the leaf is an organ of a typical plant, and the main functions are to complete photosynthesis and allow the plant to exchange gas, just like how we have the respiratory system. leaves have the stomata, which collects maintains co2 and o2 levels. this is necessary for cell metabolism. the leaf also collects sunlight using chloroplasts. succinctly, leaves own a pivotal role in sustaining plant life.

i believe it is-

d.) gravity pulled particles of dust and gas together to form planets.

i'm wiling to try and you : )