Class 10 Science Chapter 6 MCQ

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

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

There are two adrenal glands, one on top of each kidney that make adrenaline hormone. Testes are paired glands present in males, secretes male sex hormone. Pituitary grand is present just below the brain and is unpaired. It is also called master gland as it secretes a number of hormones. Ovaries are paired glands present in females, secretes female sex hormones.

There are two adrenal glands in our body one on top of each kidney. The adrenal glands make adrenaline hormones when we are faced with any dangerous situation, then our nervous system stimulates the adrenal glands to secrete more adrenaline hormone into our blood, then we can react according to the situation.

Testes are paired glands present in males, secretes male sex hormone (testosterone) which control the development of male sex organs and male features as deep voice etc. i.e. changes associated with puberty. Ovaries are paired glands present in females, secretes female sex hormone (oestrogen and progesterone). Oestrogen which control the development of female sex organs and female features as soft skin etc. And progesterone controls uterus changes during menstrual cycle and helps in maintenance of pregnancy.

During cold, mucus in nasal passage becomes too thick, so that order molecules can’t reach the olfactory receptor cells. Thus, brain receives no signal identifying the odour, and so the smell of a perfume cannot be differentiating from that of an “Agarbatti”.

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.

Involuntary action are those actions that are not under our direct control such as heartbeat, breathing, Peristatic movement etc. These are controlled by medulla. Chewing is under voluntary control and controlled by lobes present in “Cerebral cortex”.

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

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

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”.

The growth of a pollen tube towards ovule is in induced by a chemical (sugar) substance secreted by the ripened stigma of flower into the style towards ovary. It is an example of chemotropism, pollen grain response to a stimulus by growing a pollen tube in downward direction, towards ovule for fertilization.

The pathway or route taken by nerve impulse in a reflex action is called reflex arc. Reflex arcs allowed “Rapid response”.

Tendrils are the thin thread-like groups on the stem or leaves of climbing plants. These are sensitive to touch of other parts objects (i.e. thigmotropic). When a tendril touches an object, then the site in contact with object grows slowly than its other side, (i.e. rapid cell divisions in cells that are away from the support). This causes the tendril to bend towards the object by growing towards it, wind around object and cling to it.

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

The main symptom of goitre is that the neck of the person appears to be swollen due to the enlargement of thyroid gland, located in the neck. People are advised to use iodised salt for cooking food, so as to prevent goitre disease.

Abscisic is a growth inhibitor hormone. It reverses the growth promoting effects of auxins and gibberellins. It causes dormancy of seeds, wilting of leaves, closing of stomata etc.

Cerebellum controls the voluntary action e.g. posture. The cerebrum (part of forebrain) is the main thinking part of the brain. It coordinates the voluntary action of the body. It has different areas for performing different functions such as centres of hearing, smell, memory etc. The hindbrain consists of pons (takes part in regulating respirations), cerebellum (helps in maintaining posture and balance the body) and medulla that controls involuntary actions such as breathing etc. The midbrain controls reflex movements.

The cerebrum (part of forebrain) is the main thinking part of the brain. It coordinates the voluntary actions of the body. It has different areas for performing different functions such as centres of hearing, smell, memory, etc. The hindbrain consists of pons (takes part in regulating respiration), cerebellum (helps in maintaining posture and balance of body) and medulla that controls involuntary actions such as breathing etc. The midbrain controls reflex movements.

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.