'Ephemeral' means lasting for a very short time.

Metamorphosis refers to a gradual change in form or structure, often used in biological contexts.

'Meticulous' means very careful and precise in detail.

'Nostalgia' means a feeling of longing for the past.

'Quintessential' means the most perfect or typical example of a quality.

Rhetoric is the art of effective or persuasive speaking or writing, distinguishing it from other language arts.

A playwright is specifically a person who writes plays, making it the correct definition.

A novel is a type of written work that tells a story, distinguishing it from poems, essays, and articles.

An ocean is defined as a vast body of salt water, distinguishing it from lakes, rivers, and ponds.

An artist is a person who creates art, making it the correct match among the options.

An architect is specifically someone who designs buildings, distinguishing them from engineers and builders.

A programmer is specifically someone who writes computer programs, matching the definition.

Nostalgia is defined as a feeling of longing for the past.

'Ubiquitous' means existing everywhere at the same time.

An architect is specifically trained to design buildings, which matches the definition provided.

The series increases by 3 letters each time: A(1), D(4), G(7), J(10), so the next is M(13).

The series increases by 3 letters each time (A + 3 = D, D + 3 = G, G + 3 = J). So, J + 3 = M.

The differences are 3, 5, 7, which increase by 2 each time. The next difference is 9, so 18 + 9 = 27.

The series is Fibonacci: each number is the sum of the two preceding ones, so 5 + 8 = 13.

The series decreases by 10 each time. So, 70-10=60.

The series consists of prime numbers. The next prime number after 7 is 11.

The series alternates between symbols. After $, the next symbol is %.

The series is Fibonacci; next term is 3+5=8.

K is the 11th letter. 11 - 5 = 6, which corresponds to F.

Two places before D (D, C, B) is B.

The series is in reverse alphabetical order, so after X comes W.

The series is in reverse alphabetical order, so after W comes V.

All numbers except 20 are multiples of 3.

All are powers of 2 except 20.

All numbers except 30 are perfect squares.