Refer to the events given below and arrange them in the CORRECT chorological order.
(A) Invertebrates formed and active
(B) First cellular forms of life
(C) Existence of seaweeds and few plants
(D) Appearance of reptiles on earth
(E) Appearance of shrew - like mammals.

Options

A. `B rarr A rarr C rarr D rarr E`
B. `B rarr C rarr A rarr D rarr E`
C. `B rarr A rarr D rarr C rarr E`
D. `B rarr A rarr C rarr E rarr D`

Answer

To arrange the events in the correct chronological order, we need to understand the timeline of life on Earth. Here’s the step-by-step solution:

1. **First Cellular Forms of Life (B)**: The earliest forms of life on Earth were simple cellular organisms, which appeared around 3.8 billion years ago. This is the starting point of life.

2. **Invertebrates Formed and Active (A)**: After the first cellular forms, invertebrates, which are animals without a backbone, evolved. This marks the second event in our timeline.

3. **Existence of Seaweeds and Few Plants (C)**: Following the emergence of invertebrates, seaweeds and some primitive plants began to appear in the oceans. This is the third event.

4. **Appearance of Reptiles on Earth (D)**: Reptiles emerged much later, after the age of amphibians, marking the fourth event in the timeline.

5. **Appearance of Shrew-like Mammals (E)**: Finally, the appearance of shrew-like mammals occurred after the age of reptiles, making this the fifth event.

Now, putting these events in order, we have:
1. (B) First cellular forms of life
2. (A) Invertebrates formed and active
3. (C) Existence of seaweeds and few plants
4. (D) Appearance of reptiles on earth
5. (E) Appearance of shrew-like mammals

Thus, the correct chronological order is B, A, C, D, E.

**Final Answer**: B, A, C, D, E

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