Which of the following represents correct order of evolution?

Options

A. Amoeba `rarr` Leucosolenia `rarr` Ascaris
B. Leucosolenia `rarr` Hydra `rarr` Amoeba `rarr` Ascaris
C. Ascaris `rarr` Amoeba `rarr` Leucosolenia `rarr` Hydra
D. none of these

Answer

To determine the correct order of evolution among the organisms listed (Amoeba, Leucosolenia, Hydra, Ascaris), we need to follow a systematic approach based on the evolutionary timeline and classification of these organisms.

### Step-by-Step Solution:

1. **Identify the Organisms and Their Classifications**:
- **Amoeba**: A unicellular organism classified under the kingdom Protista. It is a eukaryotic organism.
- **Leucosolenia**: A type of sponge, classified under the phylum Porifera, which is part of the animal kingdom.
- **Hydra**: A simple multicellular organism classified under the phylum Cnidaria, also part of the animal kingdom.
- **Ascaris**: A roundworm classified under the phylum Nematoda (or Aschelminthes), which is also part of the animal kingdom.

2. **Establish the Evolutionary Order**:
- Evolution typically follows a pattern where simpler organisms appear before more complex ones.
- The simplest form among the listed organisms is **Amoeba**, being unicellular and a protist.
- Next in complexity is **Leucosolenia**, as it is a sponge (Porifera), which is multicellular but has a simple body organization.
- Following that is **Hydra**, which is more complex than sponges and belongs to the phylum Cnidaria.
- Finally, **Ascaris**, being a roundworm, represents a more advanced level of complexity in the animal kingdom.

3. **Construct the Correct Sequence**:
- Based on the classifications and evolutionary complexity, the correct order of evolution is:
1. **Amoeba** (Protista)
2. **Leucosolenia** (Porifera)
3. **Hydra** (Cnidaria)
4. **Ascaris** (Nematoda)

4. **Select the Correct Option**:
- Given the options provided, the correct sequence is represented by **Option A**, which lists the organisms in the order of Amoeba, Leucosolenia, Hydra, and Ascaris.

### Final Answer:
The correct order of evolution is **Amoeba → Leucosolenia → Hydra → Ascaris** (Option A).

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