Which of the following scenarios best describes a density-dependent factor limiting population growth? a. An April blizzard kills off many migrating barn swallows, which could not tolerate the cold and snow. b. A homeowner sprays her lawn with broadleaf herbicide to kill the dandelions that have started growing there that spring. c. A particularly snowy winter makes it difficult for female deer to find food, thus affecting their ability to reproduce. d. A particularly dry summer shrinks and dries up many ponds in central Canada, causing increased aggression and competition for limited nest sites among female common goldeneyes (ducks). e. A tropical storm strikes one of the Hawaiian Islands and wipes out a population of nénés that had been recovering from near-extinction.

d. A particularly dry summer shrinks and dries up many ponds in central Canada, causing increased aggression and competition for limited nest sites among female common golden eyes (ducks).

Explanation:

The density dependent limiting factor is the one which exerts it's effect on the population density based on the size and growth of the population. More the size of the population the profound will be the effect. The examples of the density dependent factors include the food availability, storm or any other natural calamity, scarcity of water, migration, disease and predation.

According to the given situation, the water is density dependent limiting factor this is because the water is available in less volume for building nests by ducks thus the ducks will compete for available water resource for building their nests. In the scarcity of water and incapability to build nests and survive the ducks may die.

step 1 ammonium can be absorbed by plants, but some is converted into nitrates which are better for plants to absorb. this is called nitrification. 2. step 2 the deer eats the plants and uses the nitrogen-containing proteins for cell growth. 3. step 3 bacteria in the soil conduct nitrogen fixation to convert nitrogen gas from the atmosphere into ammonium. 4. step 4 some of the nitrates are absorbed back into plants, but denitrification breaks down the nitrates into nitrogen gas released back into the atmosphere. 5. step 5 nitrogen is found in the urine, which gets broken down into ammonium through the process of ammonification. 6. step 6 plants absorb the ammonium and begin assimilation, the process to add the nitrogen to protein.