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.
Intelligence is most likely to be the criteria for random mating in humans.
Explanation:
If random mating is taking place on the conditions that no evolution is taking place the genetic pool will be maintained through generations.
Random mating will be based on intelligence in humans because this is the trait which gets exhibited only when showcased otherwise remains hidden while other characters like personality, appearance and athleticism are phenotypically expressed character.
Random mating is not under the influence of genotype. Intelligence is a trait which needs to be more in human as random mating takes genotype frequency in consideration.
A. Order, Arrangement, world and Universe
