Different structures and functions of roots
Explanation:
Roots are the underground descending non-green part of the plant.
Root functions: Anchorages the plant to the soil, absorbs water and nutrients from the soil.
Characteristics: Positively geotropic and hydrotropic, negatively phototropic; does not have nodes, internodes or stems.
Types:
- Tap root
- Adventitious root – fibrous, foliar and true adventitious roots
Structure and functions:
- Root cap or Calyptra: Cap-like structure covering the root tip
.
- Function: protects the meristematic tissues of the root, secretes mucilage which enhances the root tips to grow into the hard soil.
- Meristematic zone or growing point sub-terminal behind root cap. These cells are inverted and looks like a dome.
- Function – helps in the root growth by adding new cells to the root tip and other basal regions
- Zone of elongation behind the meristematic zone.
- Function – helps in elongation of the root
- Root hair zone: This is the zone of differentiation where cells differentiate into vascular tissues like phloem, xylem, endodermis, cortex etc.
- The main function of root hair is to increase the total surface area of root to facilitate more absorption of water and other nutrients from the soil
- Zone of maturation: the major and mature portion of a root.
- Function - lateral roots originates from this zone and radial differentiation leads to secondary growth.
Answer:
D. The nerves exit the central nervous system in the head and from the lumbar spine.
Explanation:
The preganglionic neurons transmit the nerve impulses through the cranial or spinal nerves that arise from the brain, to the postganglionic neurons from where the nerve fibers that relay these nerve signals to the different viscera and effector organs, located along the spinal cord
The pyramid of numbers only compares the number of organisms present in each trophic level at A PARTICULAR TIME. This pyramid can be inverted if organisms of one trophic lvl is parasitic on organisms of another trophic lvl. or when threre are many small organisms feeding of one trophic level feeding on a large organism of anoyher trophic lvl.
For eg. tree→aphid →protozoa, the pyramid of numbers is upside down
however pyramid of energy is always in a pyramid shaped as it compares the total energy in each trophic level OVER A PERIOD OF TIME. more energy is lost when we mive along a food chain hence the shape is ALWAYS pyramid.
Because people start to think that they can take them and be ok
C: Muscular System.
The ribosomes is like the production of proteins
