Question

Выберите из перечисленных характеристик те, которые относятся к классу Гидроидные:1. стадия простой медузы есть, или иногда её нет2. имеются стрекательные клетки3. доминирует крупная медуза4. доминирует полип5. глотка выстлана эктодермой 6. отсутствует стадия простой медузы

Answer 1

доминирует крупная медузка вот это подходит.

Answer 2

Ответ: Стадия простой медузы;  доминирует крупная медуза;  доминирует полип

Answer 3

Characteristics of the Hydrozoa Class

The Hydrozoa class is a group of marine animals that includes various species of hydrozoans, such as jellyfish and hydroids. Let's go through the listed characteristics and determine which ones apply to the Hydrozoa class:

1. The presence or absence of a simple medusa stage: Some hydrozoans have a medusa stage, while others do not. The medusa stage is a free-swimming, bell-shaped form of the animal. So, the first characteristic can vary among different species within the Hydrozoa class. [[1]]

2. Presence of cnidocytes (stinging cells): Hydrozoans, including those in the Hydrozoa class, possess specialized cells called cnidocytes. These cells contain nematocysts, which are used for capturing prey or for defense. When triggered, the nematocysts discharge a harpoon-like structure that injects venom into the target. Therefore, the second characteristic, the presence of stinging cells, is applicable to the Hydrozoa class. [[2]]

3. Dominance of large medusae: In some hydrozoans, the medusa stage is dominant, meaning that the medusa form is more prominent and longer-lived compared to the polyp form. However, it is important to note that this characteristic can vary among different species within the Hydrozoa class. So, the dominance of large medusae may or may not apply to all hydrozoans in the class. [[3]]

4. Dominance of polyps: In other hydrozoans, the polyp stage is dominant, meaning that the polyp form is more prominent and longer-lived compared to the medusa form. Again, it is important to note that this characteristic can vary among different species within the Hydrozoa class. So, the dominance of polyps may or may not apply to all hydrozoans in the class. [[3]]

5. Ectodermal lining of the gastrovascular cavity: The gastrovascular cavity is the central cavity of the hydrozoan body that functions in digestion and distribution of nutrients. In hydrozoans, including those in the Hydrozoa class, the gastrovascular cavity is lined with ectoderm, which is the outermost germ layer of the animal. Therefore, the fifth characteristic, the presence of an ectodermal lining in the gastrovascular cavity, is applicable to the Hydrozoa class. [[4]]

6. Absence of a simple medusa stage: Some hydrozoans do not have a simple medusa stage in their life cycle. Instead, they may have complex life cycles with various stages, such as polyps, medusae, and other forms. Therefore, the sixth characteristic, the absence of a simple medusa stage, can apply to certain hydrozoans within the Hydrozoa class. [[5]]

In summary, the characteristics that apply to the Hydrozoa class are:

- Presence of cnidocytes (stinging cells) - Gastrovascular cavity lined with ectoderm - Absence of a simple medusa stage (in some hydrozoans)

It is important to note that some characteristics can vary among different species within the Hydrozoa class, so not all hydrozoans will exhibit the same traits.

I hope this information helps! Let me know if you have any further questions.