Exams

China has been by far the biggest coal producing country over the last three decades. The country produced about 3.6 billion tonnes (Bt) of coal in 2012 accounting for over 47% of the world's total coal output.

Economic resources are those goods and services that can be converted into valuable products for individual and business purposes.

There are four major types of economic resources:

1. land,

2. labor,

3. capital and

4. entrepreneurship.

Land and labor are natural and human resources, while capital means physical resources or money.

Entrepreneurship converts these resources into usable goods.

However, resources have finite values, and proper utilization depends on economic systems and economic decisions.

A Coffin.

The study of trees is called Dendrology.

Yes, plant cells have Mitochondria.

While plant cells have chloroplasts to photosynthesize, they also require ATP for cellular functions, and do use oxygen to break down some of the sugar they produce in order to generate that ATP. They need mitochondria for this.

In particular, at night when there is no light, plants undergo cellular respiration since there is no sunlight to photosynthesize.

They do, however, produce far more sugar and oxygen through photosynthesis than they use up in respiration.

The amount of water vapor ranges from a trace amount up to 4% of the mass of air. Water vapor exists as an invisible gas in the air.

The amount of water vapor in the air is called absolute humidity. The amount of water vapor in the air as compared with the amount of water that the air could hold is called relative humidity.

The maximum amount of water vapor that can be in the air depends on the air temperature.