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The correct choice is (c) POIKILOTHERMIC

Best EXPLANATION: Frogs are poikilothermic animals. This means that they have a FLUCTUATING body TEMPERATURE which varies with the environmental conditions, or they lack CONSTANT body temperature.

The correct option is (d) They belong to class Amphibia

The BEST I can EXPLAIN: Frog belongs to class Amphibia. It lives on land and in FRESH WATER. The species Rana TIGRINA is the most common in India. Frogs are chordates and are poikilotherms. This means they do not have a constant body temperature.

Correct option is (a) 3, 6

For explanation: The nervous system of cockroach CONSISTS of a series of fused GANGLIA which are segmentally arranged. There are three ganglia present in the THORAX and six ganglia present in the abdomen.

The CORRECT CHOICE is (a) Intestinal

Best explanation: The nephridia in EARTHWORM are of three types – SEPTAL nephridia, integumentary nephridia and PHARYNGEAL nephridia. All three types are similar in structure. Intestinal nephridia is not present.

The correct choice is (d) Hypopharynx

For explanation: The hypopharynx ACTS as the TONGUE of the cockroach. It lies in a cavity surrounded by five mouth PARTS – a labrum, a LABIUM, a pair of MANDIBLES and a pair of maxillae. The head of the cockroach is a fusion of these mouth parts.

Right option is (a) Ostia

Explanation: Fat BODY, nephrocytes and uricose gland help in excretion in cockroach. Cockroaches are uricotelic, which means they EXCRETE their waste in the form of URIC acid. Ostia is a PART of the circulatory system.

Right choice is (c) Nephridium

To explain I WOULD SAY: Nephridium is the excretory organ in earthworm. NEPHRIDIA OCCUR as coiled tubules arranged segmentally. Typhlosole and gizzard are involved in digestion of food while setae help in locomotion.

Right answer is (c) They can be traced by fecal DEPOSITS

For EXPLANATION: EARTHWORMS can be traced by fecal deposits or worm castings. They are invertebrates as they lack a backbone and a bony skeleton. They live in burrows in the upper layers of the SOIL.

Right CHOICE is (d) organ SYSTEMS

The best explanation: Organs ORGANIZE to form organ systems. These organ systems in turn organize to form organisms. Organs are made of TISSUES. Tissues are made of cells.

Correct answer is (b) CLOACA

The explanation is: TWO ureters emerge from the KIDNEYS in MALE frogs. The ureters act as a urinogenital duct which opens into the cloaca. In females the ureters and oviduct separately in the cloaca.

Correct ANSWER is (b) Three

The best I can explain: The HEART of a frog has three chambers, TWO atria and one ventricle and is covered by a membrane called the pericardium. A triangular structure called as SINUS venosus joins the right atrium.

The CORRECT option is (b) False

To elaborate: A few species of cockroaches can thrive in and around the human habitat. They are pests because they spoil food and CONTAMINATE it with their smelly excreta. They can also TRANSMIT a VARIETY of bacterial diseases by contaminating the food material.

The correct answer is (d) striated

The explanation: SKELETAL muscles are attached to skeletal bones. They CONTROL voluntary ACTIONS and are striated. SMOOTH muscles are non-striated.

The correct answer is (c) Gap junctions

The explanation is: Gap junctions FACILITATE cell-to-cell COMMUNICATION by creating cytoplasmic connections for the rapid MOVEMENT of ions, SMALL molecules and SOMETIMES big molecules. Tight or occluding junctions create intercellular barriers while adhering junctions facilitate intercellular attachment.

Correct ANSWER is (c) Neural tissue

For explanation: Neural tissue exerts the GREATEST control over the body’s responsiveness to changing conditions. Neurons, the unit of the neural SYSTEM are EXCITABLE CELLS.

The correct option is (b) Hard and non-pliable

Easiest explanation: Bones have a hard and a non-pliable ground substance rich in calcium SALTS and collagen fibres which give BONE its strength. Also, the matrix of the bone is PRESENT in the form of layers called LAMELLAE.

The correct option is (b) False

Easy EXPLANATION: Simple epithelium is COMPOSED of a single LAYER of cells and functions as a lining for body cavities, ducts and tubes. The compound epithelium consists of two or more CELL LAYERS and has a protective function as it does in our skin.

The correct CHOICE is (a) midbrain

The best I can explain: A pair of optic lobes are present in the midbrain of FROGS. The forebrain contains olfactory lobes and the DIENCEPHALON while the hindbrain contains the cerebellum and medulla oblongata.

The correct choice is (c) Nasal EPITHELIUM

To explain I would say: The sensory organs in frog are eyes for VISION, tympanum and internal EARS for hearing, organs of touch CALLED sensory papillae, taste BUDS for taste and nasal epithelium for smell. The senses for vision and hearing are well developed and the rest are cellular aggregations.

Right choice is (a) conus arteriosus

The explanation: The HEART of the frog has three chambers- two auricles and one ventricle. The heart is COVERED by a covering called pericardium. OXYGENATED blood leaves the heart through the conus arteriosus.

Correct option is (a) They do not aestivate

The BEST I can EXPLAIN: Frogs have the ability to change color to protect themselves from predators. This camouflaging TECHNIQUE is called mimicry. They live in burrows to shelter themselves from extreme weather and they SHOW both AESTIVATION and hibernation.

Right choice is (d) Forewings

Best explanation: The forewings of the cockroach is called tegmina. It is dark, OPAQUE and leathery. The tegmina COVERS the hindwings. Out of the TWO PAIRS of WINGS, the cockroach uses the hindwings for flight.

Correct answer is (a) VASA deferentia

For explanation I would say: Vasa deferentia is the common prostate and SPERM duct of EARTHWORMS. Vasa efferentia is absent. Spermathecae store spermatozoa during copulation. Oviduct is a PART of the female reproductive SYSTEM.

The correct answer is (d) Ear

The explanation is: FROGS respire on LAND and in water by two different METHODS. In water, skin acts as an aquatic respiratory ORGAN. On land, the buccal CAVITY, skin and lungs act as the respiratory organs.

Correct option is (c) Two

The explanation is: The body wall of the EARTHWORM is covered externally by a thin non – CELLULAR cuticle below which is the epidermis, two muscle LAYERS – CIRCULAR and longitudinal and an INNERMOST coelomic epithelium.

Right ANSWER is (d) Nictitating membrane

Easiest explanation: EYES of frog are bulged out and are COVERED by a nictitating membrane that PROTECTS them while in water. On either side of the eyes, a membranous tympanum receives sound SIGNALS.

Correct option is (a) Macrophages are absent

Best explanation: AREOLAR tissue is a type of loose connective tissue which is present below the skin. It provides a support for epithelium and contains macrophages, mast CELLS and fibroblasts.

The correct option is (C) Neuroglial cells

The best I can explain: Neuroglial cells make up more than one-half the volume of neural TISSUE in our body. These cells protect, support and insulate the neurons. They do not CONDUCT the impulse but they can divide and hence they have regeneration power.

Correct option is (d) EPITHELIAL

To explain I would say: Epithelial tissue consists of single layer of cells and lines body cavities, ducts and TUBES. CONNECTIVE tissue, muscular tissue and NEURAL tissue are other CLASSIFICATIONS of animal tissues with different functions.

The correct choice is (a) The main FUNCTION is secretion and ABSORPTION

To explain: COMPOUND epithelium is MADE up of more than one layer of cells and thus has a limited role in secretion and absorption. Their main function is to protect against CHEMICAL and mechanical stresses. They cover the dry surface of the skin and also the moist surface of the buccal cavity.

Right answer is (c) The URINARY bladder is ventral to the rectum

The best I can explain: In frogs, the urinary bladder is THIN walled and is situated ventral to the rectum. In FEMALE frogs, the OVIDUCT and URETERS are separate, whereas in male frogs, the urinary and genital ducts fuse to form urinogenital ducts.

Correct ANSWER is (b) common bile duct

Easy explanation: Pancreatic JUICE is FIRST DELIVERED from the pancreas to the common bile duct via the pancreatic duct. The common bile duct, which also receives bile from the gall bladder delivers its contents into the duodenum.

Correct answer is (a) duodenum

Easy explanation: Duodenum is the first part of the small intestine. Food ingested by the FROG is churned with bile, pancreatic juices and hydrochloric acid in the STOMACH to FORM an acidic mixture CALLED chyme. This is passed to the duodenum.

Correct answer is (c) sclerites

The BEST I can explain: Sclerites are hard plates that join together to FORM the exoskeleton that covers the BODY of the cockroach. Sclerites are of two types- dorsal tergites and ventral STERNITES. These are joined to each other by the ARTICULAR membrane.

Correct choice is (a) 9^th to 14^th

For explanation I WOULD say: The stomach of the EARTHWORM extends from the 9^th to 14^th SEGMENTS. It is present after the gizzard, where the ingested FOOD is mechanically GRINDED before being passed through to the stomach.

The correct answer is (c) CONNECTIVE, muscular, neural, epithelial

The best I can EXPLAIN: The heart contains all four types of animal TISSUE. It contains connective, neural, muscular and epithelial tissue. It is one of the most essential organs of the human body and the center of the circulatory system. The VARIOUS types of tissues MAKING up the heart contribute to its efficient functioning.

Right option is (a) 7^th sternum

Best explanation: 7^th sternum is not involved in the formation of the genital pouch in the male cockroaches. Their genital pouch is a chamber which lies at the hind end of the abdomen. The genital chamber is BOUNDED dorsally by 9^th and 10^th terga and VENTRALLY by 9^th sternum. It CONTAINS DORSAL anus, ventral male genital pore and GONAPOPHYSIS. It is also surrounded by some phallomeres.

Right answer is (d) COMPOUND EPITHELIUM

To explain: Based on structural MODIFICATION of the cells, SIMPLE epithelium is further divided into three types. These are:

i. SQUAMOUS epithelium

ii. Cuboidal epithelium

iii. Columnar epithelium.

Right option is (a) Water

The BEST I can EXPLAIN: Frogs show external fertilization. This process takes place in water. The development of frogs involves a larval stage CALLED tadpole. Tadpoles are RESTRICTED to the water and later metamorphosize into an adult FROG.

Right OPTION is (d) Cutaneous respiration

The explanation: Frogs can BREATHE both on land and in FRESHWATER. In water, the exchange of gases OCCURS through the moist SKIN. This type of respiration shown by frogs is known as cutaneous respiration.

The CORRECT answer is (c) 2

The explanation: The earthworm POSSESSES one pair, that is, two ovaries. They are attached at the septum between the 12^th and 13^th segments. EGG cells or ova are formed which subsequently GET fertilized to zygotes during fertilization.

Correct CHOICE is (a) It lies below the gastric caeca

The explanation is: The hepatic caeca is a RING of 6 to 8 blind tubules. It is located between the foregut and MIDGUT. It secretes digested juices. However, it is not located below the gastric caeca but is also KNOWN as gastric caeca.

Right OPTION is (C) STOMACH

Easy explanation: The calciferous glands of the earthworm are present in the stomach. The food of the earthworm contains soil particles and humus. The calciferous glands neutralize the humic ACID which is present in the humus.

Correct CHOICE is (a) True

To explain: EARTHWORM is a terrestrial annelid. It does not have a backbone or a bony skeleton. Hence, it is an INVERTEBRATE. It has a long cylindrical body which is divided into several segments.

Right ANSWER is (B) Two

The explanation: The BODY of a frog is divisible into 2 parts which are head and trunk. A neck and a tail are absent. Above the mouth, a pair of nostrils is present.

Correct choice is (b) False

The explanation is: In each SEGMENT of the COCKROACH, the exoskeleton has hardened plates called sclerites that are joined to each other by a thin and FLEXIBLE articular membrane. DORSAL sclerites are known as TERGITES and ventral sclerites are known as sternites respectively.

Correct OPTION is (d) THYMUS

Explanation: Thymus and BONE MARROW are primary LYMPHOID organs. Lymph nodes, tonsils, and spleen are secondary lymphoid organs.