Question

Give reason in 1 or 2 sentences: 1.More living cells in animal body compared to plants. 2.Thick cuticle in desert plants. 3. Aquatic plants like Eichhornia can float on water. 4. Xylem is considered a complex tissue. 5. Skin is formed of stratified squamous epithelium. 6. Movements of internal organs cannot be controlled by us. 7. Sense organs are connected to neurons. 8. Muscles can bring about movement. 9. Bones which is solid and blood which is liquid both are grouped under connective tissue. 10. Some fruits like pear have gritty texture while eating.

Answer 1

1. .Animal cells are smaller than plant cells and have a membrane around them that is flexible and allows molecules, gases and nutrients to pass into the cell. Plant cells are larger and in addition to a membrane they have a rigid cell wall.
2. Desert plants have leaves that have evolved into spines, which help minimize water loss by evaporation and screen the plant from the sun. Their thorny spines also help protect them from predators.
3. Water hyacinth (Eichhornia crassipes) is an exotic free-floating aquatic plant from the Amazon River basin in tropical South America. The dark green, shiny leaves have expanded hollow stems (petioles) that enhance its ability to float and can extend to 2 m above the water level.
4. Xylem is a permanent complex tissue comprising tracheids, vessels, xylem parenchyma. It carries out the function of conducting water across the plant body.
5. The layer of keratin here is named the stratum corneum. A stratified squamous epithelium consists of squamous (flattened) epithelial cells arranged in layers upon a basal membrane. Only one layer is in contact with the basement membrane; the other layers adhere to one another to maintain structural integrity.
6. Smooth muscle tissue contraction is responsible for involuntary movements in the internal organs. It forms the contractile component of the digestive, urinary, and reproductive systems as well as the airways and arteries.
7. Sensory neurons receive impulses and carry them from the sense organs to the spinal cord or brain. Interneurons connect sensory and motor neurons and interpret the impulse. Motor neurons carry impulses from the brain and spinal cord to muscles or glands. Draw and label the structure of a typical nerve cell.
8. Like all muscles, the muscles that produce movement are made up of individual cells called muscle fibers. These fibers contract and relax. Most of the muscles involved in moving the body work in pairs. As they contract, muscles shorten, pulling against bones.
9. Blood is considered a connective tissue because it has a matrix. The living cell types are red blood cells, also called erythrocytes, and white blood cells, also called leukocytes. ... Mammalian erythrocytes lose their nuclei and mitochondria when they are released from the bone marrow where they are made.
10. his comes from stone cells, which develop in pears as they ripen on the tree. Stone cells have very thick cell membranes with very little space inside and are one of the reasons pears do not ripen well on the tree.