Question

which statement best describes an ecosystem?
it is the number of different populations in a specific area or region at a certain time.
it is the number of individuals of a given species in a specific area at a certain time.
it is the interaction of one or more communities with abiotic environmental factors.
it is a group of individuals of a population that depends on the same type of resources of a region.
3 multiple choice 20 points
a student listed some elements of a grassland biome.

• air
• grass
• insects
• soil
• water

which elements are biotic?
water and air
soil and wat
air and insects
grass and insects

Explanation:

First Question (Ecosystem Definition)

• Analyze each option:
• Option 1: Describes species richness (number of populations), not ecosystem.
• Option 2: Defines population size (number of individuals of a species), not ecosystem.
• Option 3: An ecosystem involves communities (biotic) interacting with abiotic factors (like climate, soil), so this matches.
• Option 4: Describes a guild (group with same resource use), not ecosystem.

• Biotic factors are living or once - living components.
• Air, water, soil are abiotic (non - living).
• Grass (plant, living) and insects (animal, living) are biotic.
• Check options:
• "water and air": Both abiotic.
• "soil and water": Both abiotic.
• "air and insects": Air is abiotic, insects biotic.
• "grass and insects": Both biotic.

Answer:

C. It is the interaction of one or more communities with abiotic environmental factors.

Second Question (Biotic Elements in Grassland Biome)