What is an ephemeral stream? a. one that is formed only from chemical weathering b. one that flows only after rainfall c. one that is formed only from mechanical weathering d. one that flows only in flat lands

The correct answer is option B.

An ephemeral stream is one that flows only after rainfall.

Ephemeral streams only exist for a short period of time. They are often found in the desert landscape. Desert climate is arid with sparse to no vegetation. Without plants in the soil, rain water does not get absorbed, and so after rainfall excess water flow as ephemeral streams.

B. An ephemeral stream is one that flows only after rainfall

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

the product of the pressure and volume is also constant