Question

survival of pond ecosystems
the model below represents a pond ecosystem.
pond ecosystem
select to enlarge
when a pond freezes, the ice begins to seal the surface of the pond from the surrounding environment. as the ice thickens, the pond no longer undergoes the normal exchange of gases between air and water. aquatic plants, including macroscopic algae and phytoplankton, continue to use the sunlight that passes through the ice for photosynthesis but at a slower rate. elodea, a common water weed, produces only half the oxygen in winter that it does during summer.
the ice on the pond also protects the pond life from the extremes of the cold weather. the temperature of the water under the ice hovers just above freezing. some eggs, like those of wood frogs, have a protective gel that prevents them from freezing, and the
cattails are a rooted plant commonly found in ponds. their long stems and roots store food. these plants can reproduce both sexually, through their seeds, and asexually, as new cattail plants grow upward from their stems.
based on the information above and from the passage, select two cattail traits that affect the probability of successful reproduction.
□ water is easily accessible from the pond.
□ reproduction can only happen sexually
□ long stems and roots allow for ample food storage.
□ seeds do not sprout until the weather becomes warmer.
□ cattails grow mostly above the water.

Explanation:

1. Long stems and roots allow for ample food storage: Stored food provides energy for the plant to survive harsh conditions (like frozen ponds) and support reproduction when conditions improve.
2. Cattails grow mostly above the water: Growing above water makes it easier to disperse seeds for sexual reproduction, and also supports the asexual growth of new plants from stems, both of which boost reproductive success.

The other options are incorrect: Water accessibility is a pond feature, not a cattail trait; cattails reproduce both sexually and asexually; there is no information provided about seed sprouting requiring warm weather.

Answer:

• Long stems and roots allow for ample food storage.
• Cattails grow mostly above the water.