Class 10 Science Chapter 6 MCQ

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

In human beings, nervous system and endocrine system work together to control and coordinate all the activities. Both these systems consist of a number of organs that work together in a systematic way.

Hormones are a kind of chemical messengers. A hormone is produced in one part of the body but it acts on some other part of the body. The hormones are of different types and perform different functions as per need in the body.

Testosterone is the male sex hormone. It regulates male accessory sex organs. It is responsible for secondary sexual characters like moustache, beard, etc. thus, increasing fertility in males.

The person having high sugar level in blood is called a “Diabetic”. Such persons are advised to take less sugar in diet, reduce weight, exercise regularly. Persons with severe diabetes (high sugar level in blood) are treated by giving injections of insulin. Pancreas secrete the hormone insulin. Its function is to regulate blood sugar level. Deficiency of insulin causes a disease known as diabetes that is characterized by large quantities of sugar in blood and even urine. Growth hormone secreted by the pituitary gland regulates growth and development of the body.

Pituitary gland is known as “master gland” and adrenal glands are often called “glands of emergency”

The brain is broadly divided into three regions: forebrain, midbrain and hindbrain. The forebrain consists mainly of cerebrum. The midbrain does not have any further division. The hindbrain consists of 3 centres called, pons, cerebrum and medulla.

The nervous system is made up of the longest special cell called neurons.

The information acquired at the end of the dendritic tip of a neuron causes a chemical reaction that produces an electrical impulse. This impulse travels from dendrite to cell body and then along axon to its end.

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

Abscisic acid is responsible for the formation of layer of abscission. This layer disconnects the living tissue of leaf from the other parts.

Synapses actually act like one-way valves. This is because the chemical substance is present on only one side of the gap. Due to this, the nerve impulses or messages through a particular set of neurons can go across only from one side which contains the chemical substance. In this way, synapses ensure that nerve impulses travel in only one direction through a particular set of neurons.

The movement of a plant part in response to light is called phototropism.

There are mainly two types of nerves in our body, “Cranial nerve” and “Spinal nerves”. The “Cranial nerves” connect all the parts in the head directly to brain. The “Spinal nerves” connect all the remaining parts of the body like muscles and skin to the spinal cord. But there is a also third type of nerves, called visceral nerves. Most of the visceral nerves connect the internal organs of the body to spinal cord though some also connect to “Brain”.

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

Abscisic acid is a plant hormone which functions mainly as a growth inhibitor. Abscisic acid promotes the dormancy in seeds and buds. It also promotes the closing of stomata. Abscisic Acid promotes the wilting and falling of leaves which is called “abscission”.

The main function of abscisic acid in plants is to inhibit growth. The other plant hormones with their functions are given. Such as: Auxins, promote cell elongation, root formation, cell division and other physiological process. Gibberellins, stimulate stem elongation, stem germination and flowering (opposite effect of ABA). Cytokinin, promotes cytokinesis also helps in breaking dormancy and regulating phloem transport. Abscisic acid, acts as growth inhibitor, causes dormancy of seeds, etc. promotes leaf and fruit fall, helps in stomata closing to prevent loss of H2O. Ethylene, promotes transverse growth, senescence, abscission of leaves etc.

Spinal cord is a cylindrical structure enclosed in a bony cage called vertebral column. It begins in continuation with medulla and extends downwards.

Auxin hormone increases the rate of growth in a stem but it decreases the rate of growth in a root.

A microscopic gap between a pair of adjacent neurons over which nerve impulses pass when going from one neuron to the next is called synapse. The neurons carry messages in the form of electrical signals called “electrical impulses” or “nerve impulses”. The dendrites pick up the impulses from receptor and pass them to the cell body, and then along the axon to its end. At the axonal end, electrical impulses set off release of some chemicals that crosses the gap or synapse and start a similar impulse in dendrite of the next neuron.