Oswal Model Specimen Papers ICSE Class 10 Biology Solutions (Specimen Paper - 9)

Section-A

1. (i) (c) Eating

Explanation :

Eating is not a simple reflex; it involves a complex coordination of voluntary and involuntary muscle movements, as well as sensory perception and decision-making.

(ii) (a) Alcohol

Explanation :

ADH is inhibited by the atrial natriuretic peptide which is released by the heart’s atria in response to the high blood pressure and alcohol, and other medications.

(iii) (c) Cornea

Explanation :

The most common reason for blindness is the change of the shape of the cornea called keratoconus, which can be improved by the change in the layer of the cornea.

(iv) (b) Pia mater

Explanation :

The outermost layer of the brain is called dura mater, the middle layer is called the arachnoid layer and the innermost is called the pia mater.

(v) (c) Efferent arteriole

Explanation :

It contains the lowest concentration of urea because the urea is filtered out from blood in the kidneys so the vessel that leaves the kidney will have the lowest amount of urea.

(vi) (a) Both A and R are True.

Explanation :

Capillaries are indeed the narrowest blood vessels in the circulatory system, with a diameter ranging from 5 to 10 micrometers. The reason behind this is that capillaries play a crucial role in facilitating the exchange of substances between the blood and the surrounding tissues. Their small size allows them to penetrate deep into tissues, ensuring that every cell is in close proximity to a capillary. This proximity enables efficient diffusion of oxygen, nutrients, and metabolic waste products (such as carbon dioxide) between the blood and tissues. The exchange occurs through the thin walls of capillaries, which consist of a single layer of endothelial cells, facilitating the exchange of substances by diffusion.

(vii) (c) Anaphase

Explanation :

At metaphase, the chromosomes are at the centre plate attached to the spindle fibres. And as the anaphase begins, the spindle fibres pull the chromosomes toward the poles, and the centromere divides in half.

(viii) (c) Hypertonic solution

Explanation :

The shrinkage of a cell wall from its cell wall occurs under the influence of a hypertonic solution. Due to plasmolysis, the protoplast separates from the cell wall and shrinks into a spherical form.

(ix) (b) Soil is wet, and the atmosphere is humid

Explanation :

When there is too much water in the soil for the plant to take up and the atmosphere is humid, preventing transpiration, the root pressure causes the water to squeeze out of the plant onto the tips of the leaves.

(x) (c) Contraction of the heart is powerful at the open which is on the left side

Explanation :

The contraction of the heart is the most powerful because blood from the left ventricle travels through the entire body. So, the push given to the blood by the heart must be strong enough to allow it to travel through the body.

(xi) (b) The nephron plays a vital role in maintaining water balance in the body.

Explanation :

The nephron is the functional unit of the kidney and is responsible for performing several essential functions.

The nephron plays a vital role in maintaining water balance in the body by regulating the reabsorption of water. As blood passes through the nephron, filtration occurs in the glomerulus, where waste products, ions, and water are filtered out of the blood. The filtrate then enters the renal tubules, where reabsorption takes place. The nephron selectively reabsorbs water back into the bloodstream, ensuring that the body retains the necessary amount of water for proper hydration while also eliminating excess water as urine. This water balance regulation is crucial for maintaining overall fluid balance, blood pressure, and proper functioning of bodily systems.

(xii) (b) Land and Water

Explanation :

Oil spills cause land and water pollution because in water bodies, oil layers prevent the aquatic animals to breathe properly and for land pollution it is hard to clean and can harm the plant and animals on the land.

(xiii) (d) The population of tigers decreases and the population of grass increases.

Explanation :

When the deer will no longer be there the tiger population will decrease as they will get no food and similarly, if the grass-eating animals are no longer there, the grass population will increase.

(xiv) (d) All of the above

Explanation :

The population has increased because of sufficiency of the food and the technological advancement, allowing people to live a little bit longer due to medical support. And the births of the children are more than the deaths of the old people.

(xv) (a) The menstrual cycle refers to the shedding of the uterine lining.

Explanation :

The menstrual cycle is a natural process that occurs in the female reproductive system, and it involves cyclic changes in the uterus to prepare for a potential pregnancy. If pregnancy does not occur, the thickened lining of the uterus, known as the endometrium, is shed through the vagina, resulting in menstruation or the menstrual period.

Therefore, based on the understanding of the menstrual cycle, the accurate statement is that it refers to the shedding of the uterine lining.

2. (i) (a) Telophase I

(b) Olfactory nerve

(d) Stomata

(e) Glucagon

(ii) (a) Upper epidermis, palisade tissue, spongy cells, substomatal space, stoma.

(b) Receptor, sensory neuron, spinal cord, motor neuron, effector.

(d) Prophase, metaphase, anaphase, telophase, cytokinesis.

(e) Intestinal artery, intestine, hepatic portal vein, liver, hepatic vein.

(iii) (a) Mitosis

(b) Karyokinesis

(d) Metaphase

(e) Centromere

(iv) (a) Odd: Bile; Category: Others are nitrogenous wastes.

(b) Odd: Fimbriae; Category: Others are parts of the male reproductive system.

(d) Odd: Seminal Vesicles; Category: female reproductive system.

(e) Odd: Cochlea; Category: Genetic crosses.

(v)

Column I	Column II
(a) Homologous chromosomes	(2) Chromosomes similar in size and shape
(b) Gibberellins	(3) Gibbane ring structure
(c) Bicuspid valve	(5) Allows blood flow from left auricle to left ventricle
(d) High rate of transpiration	(1) Maize plant
(e) Sacculus	(4) Static equilibrium

Section-B

3. (i) Thyroid stimulating hormone

(ii) (a) Leydig cells: Leydig cells, also known as interstitial cells, are found in the testes and are responsible for the production of testosterone, the primary male sex hormone.

(b) Auditory nerve: The auditory nerve, also known as the cochlear nerve, is responsible for
transmitting auditory information from the cochlea of the inner ear to the brain. It plays a crucial role in hearing.

(iii) (a) True, Ozone in the troposphere is considered a harmful pollutant as it contributes to air pollution and can have adverse effects on human health and the environment.

(b) False, cilia lining of the oviduct funnel push the released ovum into the oviduct.

(iv) (a) Iodine (b) Growth

(v) Plasmolysis.

4. (i) Antidiuretic hormone

(ii) (a) Chromosome: Chromosomes are thread-like structures found in the nucleus of cells that contain DNA and carry genetic information. Their main function is to package and organize the DNA, ensuring proper distribution of genetic material during cell division and inheritance of traits.

(b) Aldosterone: It helps to regulate blood pressure by managing the level of Na+ and K+ in blood.

(iii) (a) Conditioned reflex

(b) Simple reflex

(iv) (a) Alleles

(b) Sap

(v) (a) Male, because there is a Y-chromosome and an X-chromosome.

(b) (1) A female cell would have two X-chromosomes and no Y-chromosome.

(2) A sperm cell would have one X-chromosome and one Y-chromosome.

5. (i) Osmoregulation: The process of maintaining a constant osmotic condition in the body by regulating the water and solute concentration of body fluids.

(ii) (a) Menarche

(b) Puberty

(iii) (a) Diakinesis : It is the last substage of prophase in which the nuclear membrane and nucleolus disappear. A Spindle begins to be formed at the end of this stage.

(b) Bleeding : Exudation of cell sap or watery solution from the injured parts of the plant.

(iv) (a) Odd: Oxytocin; Category: Hormones released by anterior pituitary.

(b) Odd: Okazaki fragments; Category: Structural components of chromosomes.

(v) (a) Excretion is the process of removal of all harmful and unwanted products especially nitrogenous products from the body of living beings.

(b) The units of the kidney are nephrons.

(c) Malpighian capsule lies in the cortex region of the kidney and is present in large numbers, which give the cortex of the kidney a dotted appearance.

6. (i) Biodiversity: The existence of a wide variety of species of plants, animals, and microbes in a natural habitat within a particular environment is called biodiversity.

(ii) The ovum does not exert any distant chemical attraction over the sperms. Hence, to ensure that sperms reach every part of the female reproductive tract so that at least one sperm becomes available to the ovum for its fertilization, a large number of sperms are required.

(iii) (a) Carbon monoxide (CO)

(b) Renal arteries and renal veins.

(iv) (a) Drops of water on a leaf of plant like peepal does not enter the leaf by osmosis due to the presence of the cuticle, which does not allow water molecules to pass through it.

(b) Hormones are chemical substances carried to all body parts through blood circulation to bring about the harmonious working of the body.

(v) (a) The solid circle indicates the daughter is colourblind.

(b) The gene of this trait is located on the X-chromosome.

7. (i) Hydathodes: Plants release an excess of water through hydathodes when the atmosphere is very humid and transpiration process cannot occur.

(ii) Turgor pressure and Wall pressure:

Turgor pressure	Wall pressure
It is the pressure applied by the contents of a turgid cell on its wall.	It is the pressure exerted by the cell wall on its content.

(iii)

(iv) Centrosome and Centromere:

Centrosome	Centromere
It is an organelle of the animal cell.	It is a non-stainable part of the chromosome at which two chromatids join.

(v) (a) Artery

(b) Superior Venacava

Answer 8.

(i) Pollution may be defined as “an undesirable change in the physical, chemical or biological characteristics of the air, water and land that can be harmful to the health, survival or activities of humans or other living organisms.”

(ii)

Autotrophs	Heterotrophs
They contain chlorophyll, and hence can produce their own food.	They do not contain chlorophyll and hence cannot produce their own food.

(iii) (a) Ciliary muscles

(b) Aqueous Humour

$$\text{(iv)}\space (a)\space 6\text{CO}_{2} + 12\text{H}_{2}\text{O}\xrightarrow[\text{Sunlight}]{\text{ChlorophyII}}\\\text{C}_{6}\text{H}_{12}\text{O}_{6} + 6\text{H}_{2}\text{O} + 6\text{O}_{2}$$

(b) Palisade parenchyma contains a large number of chloroplasts. So, more photosynthesis takes place in the palisade parenchyma.

(v) (a) Water Pollution

(b) Detergents, Sewage, and Domestic waste cause water pollution.