Question

which of the following combinations of symbols represents an interaction in which one species benefits and the other is exploited?
○ o/+
○ -/-
○ +/+
○ +/-
question 42
1 pts
food chains differ from food webs in that
○ food webs are a single sequence of who eats whom in a community.
○ food chains better represent the entire community.
○ food webs represent the complex interactions among food chains.
○ food chains represent the complex interactions among food webs.

Explanation:

First Question (Species Interaction Symbols)

• In species interactions, the symbols represent the effect on each species (first for species 1, second for species 2).
• A “+” means benefit, “-” means harmed, “0” means no effect.
• For one species benefiting (+) and the other exploited (harmed, -), the symbol combination is “+/-” (e.g., predation, parasitism).
• “0/+” is commensalism (one benefits, one neutral), “-/-” is competition (both harmed), “+/+” is mutualism (both benefit).

• Food chains are linear sequences of “who eats whom” (e.g., grass → rabbit → fox).
• Food webs are interconnected food chains, showing complex interactions (multiple predators/prey relationships).
• Option 1: Food webs are not single sequences (food chains are single sequences).
• Option 2: Food webs (not chains) better represent the entire community.
• Option 3: Correct—food webs combine multiple food chains to show complex interactions.
• Option 4: Incorrect (food webs are made of food chains, not vice versa).

Answer:

+/-

Question 42 (Food Chains vs. Food Webs)