1. Word building.

noun	verb	adjective
		simple
	to radiate
likeness
	to appear
		developing
	to form
creature, creation

2. Make word combinations using the following words.

complex, outboard, ozon, fertilizied, modern, bright, arctic, slime, fresh, upper, direct, thin, stem, jet, powerful, main, visible

cell ice layer motor sunlight

3. Match a word in a to its definition in b.

A		B
1	boil	a	to move forward
2	radiation	b	creature, similar to snail, but it has no shell
3	to propel	c	a form of energy produced during a nuclear reaction
4	slug	d	to move in a circle around a fixed central point
5	stationary	e	the central part of a living cell, containing chromosomes
6	nucleus	f	to heat liquid until it has bubbles and starts to become a gas
7	rotate	g	things used for writing

4. Choose the correct word to complete the sentences.

gaseous advantage activity primary decomposition atmosphere metabolism nutrients available environment contained depends rely on

The ecosystem, both on land and in the water, ................ heavily upon the activity of bacteria. The cycling of ....................... such as carbon, nitrogen, and sulfur is completed by their hard labor.

When organisms die, the carbon ...................... in their tissues becomes unavailble for most other living things. ........................... is the breakdown of these organisms, and the release of nutrients back into the ..............................., and is one of the most important roles of the bacteria.

The cycling of nitrogen is another important ......................... of bacteria. Plants ..................... nitrogen from the soil for their health and growth, and cannot acquire it from the gaseous nitrogen in the .............................. The .......................... way in which nitrogen becomes .............................. to them is through nitrogen fixation by bacteria such as Rhizobium and by cyanobacteria. These bacteria convert .............. nitrogen into nitrates or nitrites as part of their ....................................., and the resulting products are released into the environment. Some plants, such as liverworts, have taken special .................................. of this process by modifying their structure to house the bacteria in their own tissues.

Working with word combinations and sentences

5. Give English equivalents to the following word combinations.

Кажущаяся простота, выше точки кипения, всплеск радиации, отделение клетки, миллиарды лет, поселиться, жерло вулкана, чайная ложка плодородной почвы, жидкая окружающая среда, изменить направление, вращать флагеллами, слизистый слой, выделять кислород.