The term 'systematics' refers to :
(a) different kinds of organisms and their classification
(b) diversity of kinds of organisms and their relationship
(c) identification and classification of organisms
(d) nomenclature and identification of animals and plants

Options

A. different kinds of organisms and their classification
B. diversity of kinds of organisms and their relationship
C. identification and classification of organisms
D. nomenclature and identification of animals and plants

Explanation

To solve the question regarding the term 'systematics', we will analyze each option provided and determine which one best defines the term.

### Step-by-Step Solution:

1. **Understanding the Term 'Systematics':**
- Systematics is a branch of biology that deals with the classification and relationships of organisms. It encompasses the study of biodiversity and the evolutionary connections between different species.

2. **Analyzing Each Option:**
- **Option (a):** "Different kinds of organisms and their classification."
- This option focuses on classification but does not mention relationships or diversity, which are key aspects of systematics.

- **Option (b):** "Diversity of kinds of organisms and their relationship."
- This option captures both the diversity of organisms and their evolutionary relationships, aligning well with the definition of systematics.

- **Option (c):** "Identification and classification of organisms."
- While identification and classification are components of systematics, this option does not address the aspect of relationships or diversity.

- **Option (d):** "Nomenclature and identification of animals and plants."
- This option pertains more to naming and identifying organisms rather than the broader study of their diversity and relationships.

3. **Choosing the Correct Option:**
- Based on the analysis, **Option (b)** is the most accurate definition of systematics as it encompasses both the diversity of organisms and their relationships.

### Final Answer:
**(b) diversity of kinds of organisms and their relationship**

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