Four characters ( a -.d) are given below . Which two are CORRECT about phylum arthropods ?
(i) it is the largest phylum of animal kingdom .
(ii) one third of all named species on earth are arthropods.
(iii)They are bilaterally symmetrical , triploblastic and segmented animals .
(iv) The body is covered by calcareous exoskeleton.

Options

A. (i) and (ii)
B. (i) and (iii)
C. (i) and (iv)
D. (i),(ii) and (iii)

Answer

To solve the question regarding the characteristics of the phylum Arthropoda, we need to analyze each of the provided statements one by one.

### Step-by-Step Solution:

1. **Statement (i): It is the largest phylum of the animal kingdom.**
- This statement is **correct**. Arthropoda is indeed the largest phylum in the animal kingdom, comprising a vast number of species, primarily insects.

2. **Statement (ii): One third of all named species on earth are arthropods.**
- This statement is **incorrect**. In fact, it is estimated that over two-thirds of all named species on Earth are arthropods, not just one-third.

3. **Statement (iii): They are bilaterally symmetrical, triploblastic, and segmented animals.**
- This statement is **correct**. Arthropods exhibit bilateral symmetry, are triploblastic (having three germ layers), and their bodies are segmented.

4. **Statement (iv): The body is covered by a calcareous exoskeleton.**
- This statement is **incorrect**. The exoskeleton of arthropods is made of chitin, not calcareous material. Calcareous exoskeletons are found in other groups like mollusks.

### Conclusion:
The two correct statements about phylum Arthropoda are:
- (i) It is the largest phylum of the animal kingdom.
- (iii) They are bilaterally symmetrical, triploblastic, and segmented animals.

Thus, the correct answer is the first and third statements.