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The CORRECT answer is (d) It stores spermatozoa during mating

The BEST I can explain: The spermathecae stores spermatozoa during mating. Four pairs of spermathecae are present in earthworms. They OCCUR in segments 6 to 9. It is not an accessory organ. It is not a VESTIGIAL organ.

Right option is (b) CLASS Amphibia

Explanation: Frogs can live both on LAND and in freshwater and belong to class Amphibia of PHYLUM CHORDATA. The most common species of frog FOUND in India is Rana tigrina.

The correct option is (d) CUTICLE

Explanation: The body wall of the earthworm is externally covered by the cuticle. It is thin and non-cellular. The epidermis lies below the cuticle. It also contains two LAYERS of muscles and an INNER coelomic epithelium.

Correct CHOICE is (B) lacunae

To elaborate: Osteocytes or bone cells are present in spaces CALLED lacunae. Lamella is a thin membrane, lacrimal sacs are present in the UPPER end of the nasolacrimal duct, while lacteals are lymphatic vessels connected to the intestines.

The correct ANSWER is (C) Tight junctions

Easiest explanation: In nearly all the animal tissues, specialised junctions provide both STRUCTURAL and functional LINKS between its cells. Tight junctions help to stop substances from LEAKING across a tissue.

Correct ANSWER is (b) Connective tissue

To explain I would say: Connective tissues are the most ABUNDANT and WIDELY distributed tissues in the body of complex animals. They are named connective tissues because of their special function of linking and SUPPORTING other tissues or organs of the body.

The CORRECT option is (a) It does not have a FREE surface

The explanation: Epithelial tissue has a free surface, which faces either a body fluid or the outside environment and thus PROVIDES a covering or a lining for some part of the body. The cells of this tissue are compactly packed with a little intercellular matrix. There are two types of epithelial TISSUES namely simple epithelium and compound epithelium.

The correct choice is (a) 16

Best explanation: The FEMALE cockroach possesses TWO large ovaries. Each ovary contains 8 ovarioles or ovarian tubules. Thus, the TOTAL number of ovarioles present in the female cockroach is double of 8, that is, 16.

Right option is (c) 3

To explain: The HEART of a FROG has three CHAMBERS- two auricles and one ventricle. The heart is COVERED by a MEMBRANE called pericardium. The heart is a muscular structure and is situated in the upper part of the body.

Right choice is (a) Carnivorous

For EXPLANATION: Frogs are carnivorous. This MEANS that their DIET CONSISTS of food which is purely of animal origin. For this reason, the length of its intestine is reduced. Thus, frogs have a short alimentary canal.

Right ANSWER is (c) Poorly developed blood vessels

For explanation I WOULD SAY: The vascular SYSTEM in cockroach is of open type. They have poorly developed blood vessels which open up into the haemocoel, where visceral organs are LOCATED. The hemolymph is colorless and contains hemocytes and plasma.

Correct ANSWER is (d) Brain

To ELABORATE: The nervous system of the EARTHWORM contains ganglia arranged on the nerve cord. It is present on the ventral side of the body. The nerve ring is present on the dorsal side. It is MADE of the nerve cord and cerebral ganglia.

Correct answer is (C) They are scavengers

The explanation: COCKROACHES are not scavengers. They are omnivores. This means that they FEED on material of both plant and animal ORIGIN. They are nocturnal ARTHROPODS and carry pathogens of several diseases.

Correct CHOICE is (C) It is PRESENT on the dorsal side

To elaborate: The nerve ring is present on the dorsal side of the BODY of the earthworm. It is made of the nerve CORD which combines with the cerebral ganglia. The nerve ring has both sensory and motor functions.

The correct answer is (c) Increases the SURFACE area for absorption

For explanation I would say: Typhlosole is present in the intestine after the 26^th segment. It arises from the median fold of the DORSAL wall. It increases the surface area of absorption of NUTRIENTS from the DIGESTED food MATERIAL.

Right ANSWER is (a) True

Best explanation: Organization is needed for the efficient output of cells and organs. This is needed for survival. Various cells with SPECIALIZED ACTIVITIES FORM tissues. Various tissues TOGETHER form organs. These organs form organ systems, which in turn form a functioning body.

Correct choice is (b) Tears

To EXPLAIN I would say: The cloaca is a SMALL, median chamber that is used to pass faecal matter, urine and sperms to the exterior in MALE frogs. In female frogs, a PAIR of oviducts arising from the ovaries open into the cloaca separately.

Correct option is (a) True

The best explanation: Frogs exhibit SEXUAL DIMORPHISM. Male frogs can be distinguished by the presence of sound-producing vocal sacs and also a copulatory PAD on the first digit of the forelimbs which are ABSENT in female frogs.

The correct option is (c) Presence of genital PORES

The explanation is: The ventral surface of the body of the earthworm can be distinguished by the dorsal surface by the presence of genital openings or pores. The genital openings in the earthworm HELP in cross-fertilisation and pores help in REMOVAL of the wastes generated in the body.

The CORRECT answer is (d) Neural coordination

To elaborate: Neural coordination is not performed by unicellular organisms because neural coordination requires a complex set of cells and tissues to CARRY out the PROCESS which is not present in a single cell. It is coordination between DIFFERENT cells of the neural tissue.

Correct option is (B) ENUCLEATED erythrocytes

Easiest explanation: Frogs have specialized vein connections between the intestine and liver and as well as between the kidneys and the LOWER parts of the FROG body, known as hepatic and renal portal systems. They have a lymphatic SYSTEM and nucleated erythrocytes.

The correct OPTION is (d) Liver

For EXPLANATION: The liver is the organ RESPONSIBLE for the secretion of bile. The secreted bile is stored in the gall bladder. Bile is a greenish-yellow fluid that acts as an emulsifying AGENT for the catabolic breakdown of FATS.

Right answer is (a) Ostia

For EXPLANATION: Out of the given structures, ostia is involved in blood circulation. It is present on either SIDE of the funnel-shaped heart chambers. The CIRCULATORY system is of open TYPE. Blood from the sinuses is PUMPED into the heart chambers through ostia.

Right choice is (B) mesothorax

The best explanation: The thorax of the cockroach is divided into three segments – prothorax, mesothorax and metathorax. The FIRST PAIR of WINGS of cockroach arises from the mesothorax. The second pair of wings arises from the metathorax.

The correct ANSWER is (c) Labrum

Best explanation: The labrum is the upper lip of the cockroach. The labium is the lower lip of the cockroach. The cockroach has SIX mouth parts – a labium, a labrum, a hypopharynx, a PAIR of mandibles and a pair of maxillae.

Right option is (d) Class – Insecta; Phylum – Arthropoda

The explanation is: Periplaneta is the scientific name for cockroach. Cockroach BELONGS to class Insecta and phylum Arthropoda. They are MOSTLY brown or black in color. They are NOCTURNAL omnivores and are COMMONLY FOUND in damp places.

Right option is (a) visible FEATURES

Explanation: Morphology is the study of form and structure. It is the study of features that are EXTERNAL and visible. Internal features and genetic features refer to the features which cannot be seen by the naked eye and are thus not INCLUDED in MORPHOLOGICAL STUDIES.

The correct option is (d) Typhlosole

The best I can explain: The characteristic feature of the intestine of an earthworm is the presence of internal median fold of dorsal wall CALLED typhlosole. Typhlosole helps in increasing the effective area of absorption for FOOD and minerals. These STRUCTURES are PRESENT after the 26^th SEGMENT except for the last 23^rd-25^th segments.

Correct ANSWER is (C) Uric acid

To explain I WOULD say: Cockroaches absorb nitrogenous waste products and CONVERT them into uric acid which is excreted out through the hindgut. Therefore, they are ALSO called as uricotelic organisms.

The correct answer is (d) Vasa deferens

For EXPLANATION I would SAY: The cuboidal EPITHELIUM is commonly FOUND in the ducts of glands, tubular PART of nephrons like DCT, collecting tubule and collecting duct. It is also found in the germinal epithelium of gonads.

The correct choice is (b) False

For explanation: Some of the COLUMNAR or CUBOIDAL CELLS get SPECIALISED for the secretion and are called as glandular EPITHELIUM. They are mainly of two types- unicellular glands and multicellular glands.

Right ANSWER is (d) TYMPANUM

To explain: The tympanum is the ear of frog. It receives sound signals from the environment. The tympanum is a membranous structure. The received ENVIRONMENTAL sound signals is then TRANSMITTED to the nervous system.

The CORRECT answer is (c) MIMICRY

The best I can EXPLAIN: Frogs have the ability to change their color to defend themselves from predators. This phenomenon is known as CAMOUFLAGE and the protective coloration using which it hides in its surroundings is KNOWS as mimicry.

Correct answer is (c) uricotelic

Easy explanation: COCKROACHES excrete waste in the form of uric acid. Hence, they are uricotelic organisms. The waste is EXCRETED from the hindgut. Cockroaches belong to the CLASS Insecta of the phylum Arthropoda.

Correct choice is (C) 3^rd, 4^th

For EXPLANATION: The NERVE cord of the earthworm bifurcates or divides into two parts at the 3^rd and 4^th segments. It then encircles the pharynx and forms the nerve ring by COMBINING with the cerebral ganglia.

The correct CHOICE is (a) glandular tissue

For EXPLANATION: CLITELLUM is a glandular tissue. It appears as a prominent dark band. The clitellum covers the 14^th to 16^th SEGMENT of the body of the mature earthworm. This glandular tissue contains SECRETORY cells.