Sometimes when I have my morning coffee, which I drink black with no sugar, I notice a thin film floating on top of the coffee.
I now realize the nature of this substance, and so I run to my wife screaming, "Look at this in my coffee!"

Hydrophobic substance

Explanation:

The coffee is a brown color powder that has a bitter taste. It is a member of the purine derivative methylated xanthines. It is a principle source of caffeine. After digestion, of caffeine in the body it get rapidly absorbed in the blood stream.

The coffee is a moderately soluble substance thus some components remain hydrophobic when dissolve in water or milk. These components form a layer over the surface of the fluid.

Based on the above description, a hydrophobic substance is the substance which can be seen as a film over the black coffee.

a

explanation:

many plants naturally reproduce this way, but it can also be induced artificially. horticulturalists have developed asexual propagation techniques that use vegetative plant parts to replicate plants. success rates and difficulty of propagation vary greatly. monocotyledons typically lack a vascular cambium and therefore are harder to propagate.