Class 8 Science Chapter 10 MCQ

The child gets one sex chromosome from the mother and one from the father. The mother has XX combination and always contributes an X-chromosome. It is the sperm of father which determines the sex of the child. This is because half of the sperms have X-chromosome and another half have Y-chromosome.

The events in sequence are: i)Maturation of egg after puberty in the ovaries of a woman. ii)Release of egg cell. iii)Fertilization of egg cell by a sperm to form a zygote. iv)Zygote divides repeatedly to form an embryo. v)Embryo is embedded in the wall of uterus for further development to foetus.

For metamorphosis of tadpoles, iodine should be present in water. This is because metamorphosis is brought about by thyroxine hormone that required the presence of iodine for its production by thyroid gland.

The most visible change during puberty in boys is sudden increase in height. At this time, the long bones elongate and make a person tall.

Adrenaline is called stress hormone which is secreted from adrenal glands at the time of stress. It helps the body to face the emergency situation or flight away from it.

The diet which contains the correct amount of each constituent (such as carbohydrates, fats, proteins, vitamins and minerals) sufficient for the normal growth and development of the body and keep a person healthy is called a balanced diet. Our Indian meal of roti (or rice), pulses (or dal), and vegetables is a balanced diet. Remember, for infants (or small babies) mother’s milk provides all the necessary nourishment which they need.

Here, all the statements are correct. Hence, your answer will be option [D].

Menarche is the beginning of the reproductive life of a girl or woman. The first menstruation or menstrual flow begins at puberty when the girl or woman is around 10 to 12 years of age. The first occurrence of menstruation at puberty is called “Menarche”. In other words, menarche is the time from which a girl or woman become capable of having a baby. Menstruation stops permanently when a woman reaches the age of about 45 to 50 years. With the permanent stoppage of menstruation, a woman lost her ability to be children. The permanent stoppage of menstruation in a woman is called “Menopause”.

Development of breasts are related to girls or women not in boys. Rest of all, are the secondary sexual characters present in male at the time of puberty.

Here, all the statements are correct. Hence, your answer will be option [D].

We know that the deficiency of thyroxine hormone causes a disease known as goitre. The main symptom of goitre disease is that the neck of the person suffering from goitre appears to be swollen. People are advised to take iodised salt for cooking food so as to prevent goitre disease. Iodised salt contains appropriate amount of iodine compounds such as potassium iodide which can provide all the iodine needed by thyroid gland to make sufficient thyroxine hormone for our body.

Here, all the statements are correct. Hence, your answer will be option [D].

AIDS stand for Acquired Immune Deficiency Syndrome. AIDS is dangerous disease which is caused by a virus called HIV. HIV stands for Human Immunodeficiency Virus. This virus is present in the blood of AIDS patient.

We know that a female has only X-chromosome in all her gametes and a male has X- chromosome as well as Y-chromosomes in male gametes. If a sperm carrying X-chromosome fertilises an egg cell which carries X-chromosome, then the zygote formed will have XX combination of sex chromosome due to which the child born will be a girl. If sperm carrying Y-chromosome fertilises an egg cell which carries X-chromosome, in the zygote formed will have XY combination of sex chromosome due to which the child born will be a boy or male.

Adrenals are endocrine glands. The adrenal glands produce adrenaline hormone. Pituitary is endocrine glands. The pituitary gland secretes a number of hormones such as testes, ovaries, thyroid gland and adrenal gland to secrete their hormones. Rest of all are correctly match.

Here, all the statements are correct. Hence, your answer will be option [D].

Here, all the statements are correct. Hence, your answer will be option [D].

Here, all the statements are correct. Hence, your answer will be option [D].

The hormones play an important role in initiating the reproductive function of adolescence at the time of puberty. The rise in the level of sex hormones is responsible for the changes in the bodies of adolescent boys and girls at puberty. The testes make male sex hormone called “testosterone” and the ovaries make female sex hormone called “estrogen”. The production of these sex hormones is under the control of another hormone called “gonadotropic hormone” secreted by pituitary gland.

In vertebrate anatomy, the pituitary gland, or hypophysis, is one piece and an endocrine gland, about the size of a pea and weighing 0.5 grams (0.018 oz) in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain. Pituitary gland is called master gland because many of the hormones which it secrets control the functioning of other endocrine glands in the body.

Here, all the statements are correct. Hence, your answer will be option [D].

Here, all the statements are correct. Hence, your answer will be option [D].