According to Robertson, the function of calciferous glands is to 

Options

A. neutralize humic acid
B. to excrete excess calcium salts
C. to digest proteins
D. to digest amylose

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the function of calciferous glands according to Robertson. We need to analyze the options provided to determine which one aligns with Robertson's findings.

2. **Reviewing the Options**: The options given are:
- Neutralize the humic acid
- Excrete excess calcium salts
- Digest protein
- Digest amylose

3. **Eliminating Incorrect Options**:
- **Digest Protein**: This option can be eliminated because the digestion of proteins is mediated by specific enzymes in the digestive system, not by calciferous glands.
- **Digest Amylose**: Similar to protein digestion, amylose digestion is also facilitated by enzymes, making this option incorrect.
- **Neutralize Humic Acid**: Although this function is associated with calciferous glands, it is attributed to Darwin's findings, not Robertson's.

4. **Identifying the Correct Function**: According to Robertson, the primary function of calciferous glands is to excrete excess calcium salts, specifically calcium carbonate. This aligns with the understanding of how these glands operate in certain organisms.

5. **Conclusion**: After analyzing all options, the correct answer is that the function of calciferous glands, according to Robertson, is to excrete excess calcium salts.

**Final Answer**: Excrete excess calcium salts.

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