Which of the following statement is false?

Options

A. osmoconformers are able to maintain homeostasis by physiological means or sometimes behavioural means also which ensure constant body temperature constant osmotic concentration etc.
B. All birds and mammals, and a very few lower vertebrates and invertebrates are capable of osmoregulation and thermoregulation
C. Thermoregulation is the major reason for the success mammals
D. Sweating and shivering are the means of thermoregulation by humans

Answer

To determine which statement is false, we will analyze each option one by one.

### Step-by-Step Solution:

1. **Examine Option 1**:
- The statement claims that osmoconformers maintain homeostasis through physiological and behavioral means to ensure constant body temperature and osmotic concentration.
- **Analysis**: Osmoconformers do not actively regulate their internal osmotic pressure; instead, they match their osmotic pressure with that of their environment. Therefore, they do not maintain constant osmotic concentration through physiological means. This statement is **false**.

2. **Examine Option 2**:
- The statement claims that all birds, mammals, and very few lower vertebrates and invertebrates are capable of osmoregulation and thermoregulation.
- **Analysis**: This is a correct statement as birds and mammals are indeed capable of both osmoregulation and thermoregulation, while some lower vertebrates and invertebrates can also perform these functions.

3. **Examine Option 3**:
- The statement claims that thermoregulation is the major reason for the success of mammals.
- **Analysis**: This is a correct statement. Thermoregulation allows mammals to maintain a stable internal environment, which contributes to their success in various habitats.

4. **Examine Option 4**:
- The statement claims that sweating and shivering are the means of thermoregulation in humans.
- **Analysis**: This is also a correct statement. Sweating helps cool the body in hot conditions, while shivering generates heat in cold conditions.

### Conclusion:
After analyzing all options, we find that **Option 1** is the false statement. Osmoconformers do not maintain homeostasis through physiological means; they conform to the osmotic pressure of their environment.

### Summary of the False Statement:
- **False Statement**: Osmoconformers are able to maintain homeostasis by physiological means and sometimes behavioral means, which ensure constant body temperature and constant osmotic concentration.