VII. Match the word (1-8) and its definition (a-h):

1. mutagen	a. any substance, such as manure or a mixture of nitrates, added to soil or water to increase its productivity
2. mutagenesis	b. any of a group of submicroscopic entities consisting of a single nucleic acid chain surrounded by a protein coat and capable of replication only within the cells of living organisms: many are pathogenic
3. mutant	c. a substance or agent that can induce genetic mutation
4. fertilizer	d. any form of cancer of the lymph nodes
5. cancer	e. a coating or discoloration caused by various saprotrophic fungi that develop in a damp atmosphere on the surface of stored food, fabrics, wallpaper, etc
6. virus	f. the generation, usually intentional, of mutations
7. lymphoma	g. any type of malignant growth or tumour, caused by abnormal and uncontrolled cell division
8. mould	h. an animal, organism, or gene that has undergone mutation

VIII. Translate the following text into English using the words from the text:

Мутагени – фізичні і хімічні чинники (factors), що викликають стійкі спадкові зміни – мутації. У 1927 Герман Меллер отримав мутації у дрозофіли дією рентгенівських променів. Мутагенами можуть бути різні чинники, що викликають зміни в структурі генів, змінюють структуру і кількість хромосом. За походженням мутагени класифікують на ендогенні (endogenous), що утворюються в процесі життєдіяльності організму і екзогенні (exogenous) – всі інші фактори, в тому числі і умови навколишнього середовища.

IX. Read the text using a dictionary and speak on it: Mutagenesis in Amphibian Populations

In the past several decades, decline in amphibian populations has been occurring all over the world, for unexplained reasons but of which pesticides may be a part. For example, atrazine, an organic compound commonly used as an herbicide, has adverse effects on the sexual development of frogs: when exposed to even low levels of the substance, as many as 20% of frogs developed additional ovaries or testicles, or became hermaphrodites – individuals with both male and female reproductive organs. In addition, a drop in testosterone levels in male frogs due to the atrazine caused their larynx to shrink, reducing the frogs' ability to produce mating calls.

There is evidence of chemical pollutants causing frog developmental deformities (extra limbs, or malformed eyes).

They also discovered that frogs and other amphibians were sensitive to these chemical pollutants and pesticides because they lived both on land and in water.

Now herpetologists believe that increased UV radiation is affecting the frogs’ eggs, which float on the surface of the water absorbing the UV rays.

Notes to the texts:

amphibian – амфібія

adverse – шкідливий; несприятливий

ovary – яєчник

testicle – яєчко

hermaphrodite – гермафродит

a drop – зниження, падіння

larynx – гортань, глотка

limb – кінцівка, частина (тіла)

malformed – потворни

to shrink – скорочувати(ся)

evidence – доказ; свідчення