Explanation

Smoking (especially of tobacco or cannabis) is often considered a gateway behavior that can lead to experimenting with harder substances.

It is widely observed as a first step in the path toward more serious drug addiction.

Explanation

A hypothesis is a testable and specific explanation for a scientific observation or question.

It can be confirmed or rejected through experiments and data collection.

Explanation

Blood carries oxygen from the lungs and nutrients from the digestive system to all body cells.

It also removes carbon dioxide and waste products, helping maintain overall body function.

Explanation

Amoeba is a unicellular organism, meaning it consists of only one cell.

It performs all life processes like movement, feeding, and reproduction within that single cell.

Explanation

Observation is the second step where scientists collect facts using senses or tools.

It leads to forming a hypothesis, a possible explanation to be tested.

The Steps of the Biological Method:

1. Recognition of a problem
2. Observation
3. Hypothesis formation
4. Deduction
5. Experimentation
6. Data collection and analysis
7. Conclusion
8. Theory/law formation (if repeatedly confirmed)

Explanation

Euglena is a unicellular organism, a key characteristic of many Protista.

Although it is eukaryotic and lives in water, being unicellular is the main reason it’s classified under Protista.

Explanation

One human leg has 31 bones including the femur, tibia, fibula, patella, tarsals, metatarsals, and phalanges.

These bones support movement and bear the body’s weight.

Explanation

Water makes up about 70% of the cell's composition.

It is crucial for various cellular processes, including biochemical reactions and maintaining cell structure.

Explanation

In terrestrial ecosystems, plants are the main producers that convert sunlight into energy via photosynthesis.

They form the base of the food chain and support all other life forms.

Explanation

White blood cells (WBCs) are the body's defense cells that fight infections and diseases.

They identify and destroy harmful bacteria, viruses, and other pathogens.