Consider the following ecosystems: 1. Taiga 2. Tropical evergreen 3. Tropical deciduous 4. Tundra The correct sequence in decreasing order of the albedo values of these ecosystems is:

Answer: (c) 4, 1, 3, 2

Tundra (snow) > taiga (dark conifers, but snowy clearings) > tropical deciduous (lighter, leafless in the dry season) > tropical evergreen (dark canopy).

The idea

Albedo is the share of sunlight a surface reflects. White and bright surfaces reflect most of it; dark surfaces absorb most of it. So rank the four by how light or dark they look from above.

Tundra: snow for most of the year → highest → Taiga: dark conifers with snow between them → Tropical deciduous: bare and pale in the dry season → Tropical evergreen: dark, closed canopy all year → lowest

Why the others are wrong

(a) Puts taiga above tundra — tundra is snow-covered for most of the year.

(b) Puts evergreen forest above deciduous — the dark closed evergreen canopy reflects least.

The trap

The last pair is the test: the evergreen canopy is the darkest surface.

Also know

The Earth as a whole reflects about 30% of sunlight. Albedo drives a feedback: when ice melts, darker sea or land is exposed, which absorbs more heat and melts more ice. Soot settling on snow has the same effect.