<span>CFCs and smog are examples of air pollution.
CFCs (containing atoms of carbon, chlorine and fluorine)are a component of aerosols sprays, refrigerants etc. These chemical compounds are non reactive in the lower atmosphere but the CFCs react with UV radiation in the sunlight and release inorganic chlorine. This chlorine is the main cause of the holes present in the ozone shield (shield that protects us from harmful UV rays) in the polar regions.
Smog refers to the haze or fog that occurs as a result of air pollution (caused by burning of fossil fuels etc)</span>
Answer:
C. Exocytosis uses transport vesicles to export materials from the cell
Explanation:
Exocytosis is the reverse process of endocytosis including the expulsion of the material that is membrane -encapsulated (material is packaged in the vesicles ) inside the cell out of the cell. It has following steps :
1) The cell forms a vesicle around a material which is to be expelled.
2) The vesicle is transported to the cell membrane.
3) The vesicle membrane fuses with the cell membrane and releases the contents from the cell.
Hence option C. Exocytosis uses transport vesicles to export materials from the cell IS THE RIGHT OPTION.
Answer:
1. chromosome: tight coils of DNA
2. Eukaryote: a cell that has a membrane-bound nucleus
3. Gene: a specific sequence of DNA nucleotides that carry hereditary traits
4. Prokaryote: a cell whose nucleus is not bound by a membrane
5. Trait: genetic characteristic of an individual
Explanation:
Chromosomes are the thread-like structures that appear during cell division. Each chromosome is made up of DNA tightly coiled with its packing proteins.
A cell is defined as eukaryote or prokaryote on the basis of the presence of a membrane-bound nucleus. The cells that lack the membrane-bound nucleus and other membrane-bound organelles are called prokaryotic cells. Example: bacteria.
The cells that have a membrane bound nucleus in which DNA is present are called eukaryotic cells. Example: Plant cells.
A stretch of DNA that code for a particular protein and thereby regulate specific genetic trait is called a gene. Genes are present on chromosomes and are carried from one generation to next to maintain the genetic traits.
The features of living beings regulated by the gene are called trait. Example: skin color, eye color, etc.
The type of joint that allows bones to move backward and forward in only one direction is the hinge joints. Ball and socket are the joints that allows movement in all directions. Gilding joints are type of joints that are the vertebral disks that allow twisting, turning, and sliding. Hinge joints are formed between two or more bones where the bones can only move along one axis to flex or extend. They include the ankle, elbow and knee joints.
