1. The digested food is absorbed in the small intestine, mainly through the inner walls lined with tiny finger-like projections called villi. These villi greatly increase the surface area for absorption. Each villus contains blood capillaries and lymph vessels that transport nutrients. The digested nutRead more

    The digested food is absorbed in the small intestine, mainly through the inner walls lined with tiny finger-like projections called villi. These villi greatly increase the surface area for absorption. Each villus contains blood capillaries and lymph vessels that transport nutrients. The digested nutrients such as glucose, amino acids, fatty acids, and glycerol pass through the intestinal wall into the bloodstream and lymph. From there, they are carried to different parts of the body for energy, growth, and repair.

    See less
    • 123
  2. Boiled eggs are rich in proteins. Protein digestion begins in the stomach. The gastric glands present in the stomach wall secrete gastric juice containing pepsin enzyme and hydrochloric acid. Hydrochloric acid creates an acidic medium, which activates pepsin from its inactive form, pepsinogen. PepsiRead more

    Boiled eggs are rich in proteins. Protein digestion begins in the stomach. The gastric glands present in the stomach wall secrete gastric juice containing pepsin enzyme and hydrochloric acid. Hydrochloric acid creates an acidic medium, which activates pepsin from its inactive form, pepsinogen. Pepsin then breaks down complex protein molecules into smaller peptides. The mucus secreted by the stomach lining protects it from acid damage. Thus, the stomach is the first site where protein digestion starts effectively in humans.

    See less
    • 129
  3. ANSWR: (b) Eggs contain fats. Bile juice from the liver breaks down large fat globules into smaller ones for increasing the efficiency of the enzymes and making the medium alkaline. Emulsified fats are digested by lipase secreted by pancreas. ANSWER: (c) Sweet potatoes are rich in starch. The salivaRead more

    ANSWR: (b) Eggs contain fats. Bile juice from the liver breaks down large fat globules into smaller ones for increasing the efficiency of the enzymes and making the medium alkaline. Emulsified fats are digested by lipase secreted by pancreas.

    ANSWER: (c) Sweet potatoes are rich in starch. The saliva secreted by salivary glands present in buccal cavity contain an enzyme called salivary amylase that breaks down starch which is a complex molecule to give sugar.

    ANSWER: (d) Small Intestine will have a maximum amount of digested food as the process of digestion is completed in the small intestine.

    See less
    • 126
  4. (i) Puneet should not choose seeds as banana plants have lost the capacity to produce seeds. He should go for vegetative propagation of banana (by stem cutting). (ii) Errors and variations in DNA copying cause variation. Variation is good as it can help a population tide over unfavourable conditionsRead more

    (i) Puneet should not choose seeds as banana plants have lost the capacity to produce seeds. He should go for vegetative propagation of banana (by stem cutting). (ii) Errors and variations in DNA copying cause variation. Variation is good as it can help a population tide over unfavourable conditions by survival of some variants. It is bad as parents’ desirable characters are lost/ sometimes variants are not able to survive in the new conditions/ the variant is not able to use the cellular apparatus efficiently.

    See less
    • 53
  5. Watermelon has unisexual flowers; the male and female flowers are separate. The presence of pollinators will facilitate cross pollination between the flowers increasing the chance of fertilization and number of fruits being produced. Without pollinators the probability of pollen falling on stigma reRead more

    Watermelon has unisexual flowers; the male and female flowers are separate. The presence of pollinators will facilitate cross pollination between the flowers increasing the chance of fertilization and number of fruits being produced. Without pollinators the probability of pollen falling on stigma reduces in a unisexual flower, especially if they are far apart thus the number of fruits produced will be less. (ii) The three changes observed are: ● Ovule develops a tough coat and becomes seed. ● Ovary grows and ripens to form fruit. ● Petals, sepals, stamen, style and stigma may shrivel and fall off.

     

    See less
    • 111