The lava lamp has a light bulb as a heat source at its base. the lamp contains a colored, waxy fluid that can be observed moving in clumps through a clear liquid. as the clump of colored fluid at the bottom of the lava lamp reaches the top, which has increased? its density its temperature the kinetic energy of its molecules the space between its molecules

The density will increase

Explanation:

As mentioned in the question, the lamp contains a colored, waxy fluid that can be observed moving in clumps through a clear liquid. The clump of colored fluid reaches to the top from the bottom of the lava lamp, this happens because the clump is heavier so it will absorb maximum amount of heat and using that heat it will expand. When things expand they become less dense and start to rise. So,initially its density will lower but when  it will keep rising in such a way that when it reaches top, it becomes more dense and heavy since it has cooled down till that time.

Hope it help!