F1-2 science 7.4-7.7 Fill in the blanks

greenhouse effect

The increasing amount of carbon dioxide in the atmosphere enhances the ____________.

Air pollutants

____________ will bring many health risks to human bodies.

capillaries

In the lungs, there are millions of air sacs. Their surfaces are covered with ____________.

nitrogen

Air is mainly composed of ____________, together with oxygen, carbon dioxide, noble gases, water vapour and other small amounts of gases.

oxygen

During respiration, food is broken down in the presence of ____________ to form water and carbon dioxide.

chemical

The ____________ energy stored in the food is changed to useful forms of energy for body activities in respiration.

light energy

Plants use ____________ to turn carbon dioxide and water into food in photosynthesis.

oxygen

____________ is produced as a by-product of photosynthesis.

carbon dioxide

Living things release ____________ during respiration, which is used by plants for photosynthesis.

oxygen

Plants produce ____________ via photosynthesis to make up for the gas used by living things in respiration.

Photosynthesis

Process which involves the uptake of carbon dioxide by plants is ____________.

Respiration

Process which involves the uptake of oxygen by plants is ____________.

inflate / expand

When air is injected into cow lung tissue through bronchioles, the lung tissue will ____________.

air sacs

Tar in cigarette smoke coats the ____________ in lungs and affects gas exchange.

Nicotine

An addictive chemical in cigerette smoke.