Final answer:
The adjective that describes something as forever lasting and unchanging is 'perpetual'. Other options like 'ephemeral', 'mutable', and 'transient' carry meanings of temporary or changeable nature.
Step-by-step explanation:
A) Ephemeral: This adjective describes something that is fleeting, transitory, or lasting for a very short period. An ephemeral thing is temporary and does not endure for a long time.
B) Perpetual: This adjective refers to something that is continuous, constant, and enduring forever. Perpetual implies a state of being unchanging and everlasting.
C) Mutable: Mutable is an adjective used to describe something that is liable to change or capable of being changed. It suggests a capacity for alteration or transformation.
D) Transient: Transient describes something that is temporary, lasting only for a short duration. It implies a brief existence or a passing nature.
The adjective that means forever lasting and changeless is B) Perpetual. The word perpetual implies continuous and unending duration without change. Let's look at the other options for clarification: A) Ephemeral means short-lived or fleeting; C) Mutable means subject to change or variation; and D) Transient means temporary or not lasting.