Упр.9 Юнит 3.2 ГДЗ Starlight Баранова 11 класс

Multiple choice cloze 9

RNE

Read the text with the gaps marked by numbers 1–7. Choose the correct answer.

Heredity

The genes for certain characteristics are passed down from parents to children. For example, parents with brown eyes often 1) to children. 2) though, this doesn’t work and parents with brown eyes can have a blue-eyed baby. This is explained by a principle called segregation. Hereditary traits are 3) by specific genes and each individual carries two genes for each trait, one from each parent. When an individual reproduces, the two genes split up or segregate into the two types of male and female cells that join 4) to make a new individual.

Inherited characteristics come from specific genes. There is a different gene for each different characteristic. There is a gene for height, a gene for hair colour, a gene for eye colour and so on. Variations of the gene for the same trait are 5) alleles. In each gene 6), one of the two genes is dominant over the other. The dominant allele will hide the recessive allele. For example, if the father gives a brown allele of the eye colour gene, and the mother gives a blue allele, the child will have brown eyes. This is because brown eye colour is dominant and blue is recessive. Sometimes two genes are co-dominant, as in the case of skin colour, for example. The child of a dark-skinned person and a pale-skinned person, therefore, will be a 7) of the two.