Explanation

Tetanus is caused by the bacterium Clostridium tetani.

The other options are caused by different pathogens:

• Malaria is caused by a parasite (Plasmodium) transmitted through mosquito bites.
• Cancer is not caused by bacteria; it is a group of diseases involving abnormal cell growth.
• Rabies is caused by a virus (Rabies virus), not bacteria.

Explanation

Explanation

Emphysema is a common respiratory problem among smokers.

It is a type of chronic obstructive pulmonary disease (COPD) that causes shortness of breath and makes it difficult to breathe.

Emphysema damages the air sacs in the lungs, which can lead to:

1. Shortness of breath
2. Wheezing
3. Coughing
4. Chest tightness

Smoking is the leading cause of emphysema, as it damages the lung tissue and leads to inflammation.

Explanation

Chlorine atoms in Chlorofluorocarbons (CFCs) are primarily responsible for the depletion of the ozone layer. 

Explanation

Calcium is the most abundant mineral in the human body, making up 1.5 to 2% of the total body weight.

Approximately 1,200 g of calcium is present in the body of an adult human; more than 99% of that amount is found in bones.

Explanation

Spiders, ticks, and mites belong to the class Arachnida.

They are characterized by having eight legs and a body divided into two main segments.

Explanation

Pesticides are chemicals used to kill or repel insects that damage plants and crops.

They help protect agricultural yield by controlling pest populations.

Explanation

The ozone layer is located in the stratosphere, about 10 to 30 miles above Earth's surface.

It protects the Earth by absorbing most of the Sun's harmful ultraviolet (UV) radiation.

Explanation

The pinna is the outer part of the ear that collects sound waves and directs them into the ear canal.

From there, sound waves travel to the ear drum and further into the inner ear for processing.

Explanation

Asexual reproduction in plants is commonly referred to as vegetative propagation or vegetative reproduction.

It involves the formation of new plants from parts of the parent plant, like stems, roots, or leaves, without the involvement of seeds.