In this task, you are given two facts, and a multiple-choice question. Based on the given facts, answer the question with index of the correct option (e.g, "A").

Let me give you an example: Fact1: a plant requires sunlight to grow, Fact2: Plants to avoid are fast-growing vines that can take over an area in no time., Question: What requires sunlight in order to take over an area? (A) spores (B) fish (C) plants (D) humans (E) pods (F) Oak (G) opossums (H) coral
The answer to this example can be: C
Here is why: This is a good example. Based on the facts plants require sunlight in order to take over an area.

OK. solve this:
Fact1: moss causes chemical weathering, Fact2: Mosses Mosses are flowerless plants that grow in clumps., Question: What effects can flowerless plants growing in clumps have on their environment? (A) chemical weathering (B) decreased differentiation (C) Ugliness (D) looseness of dirt or compost (E) Wealth (F) organisms and their habitat (G) Greenhouse gases (H) Al Gore
Answer:
A