Answer 17. Domain Bacteria and Archaea.
Bacteria and archaebacteria includes single celled organisms in which membrane bound cell organelles such as mitochondria, chloroplast are absent. membrane bound nucleus is also absent. They have incipient nucleus.
Answer 18. Viruses.
Viruses are not included in Domain as they are not cellular organisms. viruses are connecting link between living and non-livings.
Answer 21. Mouth, Esophagus, Stomach, Small intestine, Large intestine.
Answer 23. Fungi, Protists.
Fungi are either saprophytes or parasites. Hence, they are nutritionally heterortrophic. Protists are either autographs or heterotrophs.
Answer 24. It extracts oxygen from the atmosphere for use by body cells. Oxygen is inhaled during breathing. It reaches to the lungs where exchange of gases occurs.
