Carbon dioxide assimilation occurs through
(a) Krebs cycle
(b) Calvin cycle
(c) Glycolysis
(d) Anaerobic respiration

Options

A. Krebs cycle
B. Calvin cycle
C. Glycolysis
D. Anaerobic respiration.

Answer

To determine through which process carbon dioxide assimilation occurs, let's analyze each option provided:

1. **Krebs Cycle (Option A)**:
- The Krebs cycle, also known as the citric acid cycle, is part of aerobic respiration. It involves the breakdown of acetyl coenzyme A to produce energy carriers like ATP, NADH, and FADH2, along with the release of carbon dioxide as a byproduct. However, it does not assimilate carbon dioxide; rather, it releases it. Therefore, this option is incorrect.

2. **Calvin Cycle (Option B)**:
- The Calvin cycle is specifically involved in the process of carbon dioxide fixation and assimilation in plants. It consists of three main stages: carbon fixation, reduction, and regeneration of ribulose bisphosphate (RuBP). In this cycle, carbon dioxide is incorporated into organic molecules, making this the correct process for carbon dioxide assimilation.

3. **Glycolysis (Option C)**:
- Glycolysis is a metabolic pathway that breaks down glucose into pyruvate, producing a small amount of ATP and NADH in the process. It occurs in the cytoplasm and does not involve the assimilation of carbon dioxide. Therefore, this option is also incorrect.

4. **Anaerobic Respiration (Option D)**:
- Anaerobic respiration occurs in the absence of oxygen and involves the breakdown of glucose to produce energy, resulting in byproducts like ethanol or lactic acid, along with carbon dioxide. However, this process does not assimilate carbon dioxide; rather, it produces it. Thus, this option is incorrect as well.

Based on the analysis, the correct answer is:
**(b) Calvin cycle**