Biology: Sensory Systems and Environmental Conservation

The iris is the coloured circular structure concentrically surrounding the center of the eye, the pupil, which appears to be black. The size of the pupil, which controls the amount of light entering the eye, is adjusted by the iris's dilator and sphincter muscles. A device known as an ophthalmoscope is used to see inside the eye. Therefore, the correct answer is option B.

Meissner corpuscles are one of the three types of cutaneous receptors which are sensitive to fine touch. Three types are cutaneous receptors are sensitive to pressure which are namely Pacinian corpuscles, Ruffini endings and Krause end bulbs. Out of these, onion-shaped Pacinian corpuscles lie deep inside the dermis. The Ruffini endings are present deeper in epidermis near the base while the Krause end bulbs are present in specialized regions only, for example, conjunctiva of eyes, mucous membrane of lips and tongue etc. Thus, the correct answer is option D.

In mammals, tactile receptors are most densely concentrated on the face, particularly around the mouth and nose, to facilitate sensory input for feeding and environmental interaction.

• Sensitivity to temperature is a skin sense that is related to the human need to maintain internal temperature balance or thermal homeostasis. 
• When the body becomes hotter than the normal temperature the sweat glands releases sweat which in turns cools the skin as it evaporates. This helps the lower internal temperature of the body
  
• Hence the organ which senses temperature is skin.
• So, the correct answer is 'Skin'.

(A)Chemoreceptor - Receptor that responds to chemicals.

• Otorhinolaryngology is a surgical subspecialty within medicine that deals with the conditions of the ear, nose and throat (ENT) and related structures of the head and neck. It is also called as otolaryngology. Otorhinolaryngologist treats the disease of the ear, nose, throat, base of the skull and for the surgical management of cancers and benign tumours of the head and neck. Hence, otorhinolaryngology is the study of disease of the ear, nose and throat.
  
• So, the correct answer is 'study of disease of the ear, nose and throat'.
  

Mechanoreceptor - Receptor that responds to pressure,touch,  position, acceleration.

Taste buds are sensory organs that are found on your tongue and allow you to experience tastes that are sweet, salty, sour, and bitter. Taste buds have very sensitive microscopic hairs called microvilli. Those tiny hairs send messages to the brain about how something tastes, whether if it is sweet, sour, bitter, or salty.

Statio-acoustic receptors are meant for both sensory functions, i.e., hearing (sound) and maintenance of body balance (equilibrium) of the body. These receptors generate stimuli in response to sound and gravity. The function of  stato-acoustic receptor is hearing and balancing.

There are the different type of stimulus receptors they are mechanoreceptors, chemoreceptors, thermoreceptors, photoreceptors, and electroreceptors. Here, the pressure is a type of mechanoreceptors. Pacinian corpuscle commonly found in deeper tissues of the tendons and ligaments which senses deep pressure. Meissner's corpuscle senses light touch and motion. Bulbs of Krause senses cold and low-frequency vibration. 

Chemoreceptors are the receptors that respond to chemicals. Both taste and smell are related to chemical receptors. Therefore, they are chemoreceptors.

(A)Chemoreceptor - Receptor that responds to chemicals.

(A)Chemoreceptor - Receptor that responds to chemicals.

• There are two types of photoreceptor cells in the human eye. They are rods and cones.
  
• The daylight (photopic) vision and colour vision are functions of cones and the twilight (scotopic) vision is the function of the rods.
  
• There are three types of cones which possess their own characteristic photopigments that detect red, green and blue lights.
• Hence various colours can be detected by Eyes.
• So, the correct answer is 'Eyes'.

• Sense organs are organs of the body which responds to external stimuli by conveying impulses to the sensory nervous system. For example, eyes, nose, tongue, and ear.
• We see with our eyes, we smell with our noses, we listen with our ears, we taste with our tongue, and we touch with our skin. Our brain receives signals from each of these organs and interprets them to give us a sense of what's happening around us.
• So, the correct answer is 'All the above'.
  

• The upper surface of the tongue has small projections called papillae, some of which bear taste buds.
• About 50 -150 taste cells are found in a taste bud. These cells detect all 4 tastes i.e sweet, sour, salty and bitter.
• Hence tongue helps to identify the taste of food.
• So, the correct answer is 'Tongue'.

• Sense organs are organs of the body which response to external stimuli by conveying impulses to the sensory nervous system.
• We see with our eyes, we smell with our noses, we listen with our ears, we taste with our tongue, and we touch with our skin. Our brain receives signals from each of these organs and interprets them to give us a sense of what's happening around us.
  
• Hence Organs that helps to detect stimulus from surroundings is called as sense organs.
• So, the correct answer is 'Sense organs'.

• Photoreceptors - These are the structures responsible for light sensitivity.
  
• Meissner's corpuscle - They are located in the upper surface of the skin and is sensitive to touch.
  
• Olfactory organs - The organs that are responsible for the detection of smell.
  
• Pacinian corpuscles - They are embedded deeply into the skin, below the layer of dermis or hypodermis. They act as the receptors for pressure on the skin.