CBSE Class X – Science Biology Exam ( Full Syllabus)

In human beings, sex of the individual is genetically determined as the genes inherited from our parents decide whether we will be boys or girls.

The Foremost attribute are always supreme. Tallness is a dominant trait as a single copy of ‘T’ is enough to make the plant tall, while two copies have to be ‘t’ for the plant to be short.

Radish and carrot represent the correct homologous structures because both have similar design or structure, though both are of different species.

The character of the cross will be cross fertilization, which is the transfer of pollen from one plant to the stigma of fower; borne on a distinct plant of the same species.

The genotype ratio of F2 generation is: TT : Tt : tt = 1 : 2 : 1. Therefore, the ratio of TT and tt plants of F2 generation will be the same. 4. Two pink coloured fowers on crossing resulted

only one parent is involved in the Asexual reproduction ,there is no fusion of male and female gamates.

Hepatitis is not a sexually transmitted disease. It is a water-borne viral disease compared to other options.

Organisms look similar because they have similar body designs. As the DNA in the cell nucleus is the information source for making proteins and therefore this information source is changed, different proteins will be made which will lead to altered body designs.

Reproduction is linked to the stability of populations of species., but variation is useful for the survival of species.

Rice water contains starch, hence when iodine solution is added to rice water it turns blue-black.

Anaerobic respiration (in absence of oxygen) in yeast is known as fermentation as ethanol (alcohol), carbon dioxide and 2 ATP molecules of energy is produced from glucose

Pancreas secretes pancreatic Juice which contains trypsin, lipase and pancreatic amylase. Trypsin digests the proteins, lipase breaks down the fat droplets already emulsifed by bile salts and pancreatic amylase breaks down the starch.

Small intestine receives Juices from liver, pancreas and walls of small intestine. Bile Juice from liver emulsifes the fats and makes the medium alkaline. Pancreas and small intestine Juices contain amylase, lipase and tryspin

Digestion of food starts in mouth by salivary amylase. From here it enters into the stomach via oesophagus The simpler substances formed by chemical digestion are then absorbed by small intestinal villi.

During inhalation, the ribs move out and the diaphragm fattens. As a result, the surface area for gaseous exchange increases. The site for gaseous exchange in the lungs are alveoli._x000D_During inhalation, ribs move inward and diaphragm is raised_x000D_In the alveoli, exchange of gases takes place i.e. oxygen form alveolar air difuses into blood and carbon dioxide from blood into alveolar air._x000D_Haemoglobin has greater aǝinity f or carbon dioxide than oxygen_x000D_Alveoli increases surface area for exchange of gase

The examples and the relation of animal group and heart are as Fishes have two chambered heart and exhibit single circulation while three chambered heart of amphibian and reptiles and four chambered heart of birds and mammals exhibit double circulation.

Fishes have only two chambers to their hearts, and the blood is pumped to the gills, is oxygenated there, and passes directly to the rest of the body. Thus, blood goes only once through the heart in the fsh during one cycle of passage through the body.