Periodic Classification of Elements — Science STD 10 — Question

State the three common features of all the respiratory organs like skin, gills and lungs.

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Reactants	products	Type of chemical reaction
Fe+S	NaCl+H_(2)O	Oxidation
CuSO_(4)+Zn	2CuO	Neutralization
2Cu+O_(2)	ZnSO_(4)+Cu	Displacement
HCl+NaOH	FeS	Combination

Draw a simple diagram of the human eye and label clearly the cornea, iris, pupil, ciliar muscles, eye-lens, retina, optic nerve and blind spot.

i. What is biotechnology?
ii. Give any two commercial applications of it.

Read the statements and answer accordingly:
i. Calcareous spines are present on the body. Tube feet are used for locomotion and capturing prey also.
- Identify the phylum and give one example.
ii. I live in your small intestine. Pseudocoelom is present in my thread like body.
- Identify the phylum and give one example.
iii. My body is spindle shaped. I respire with the help of gills.
- Identify my class and give one example.

With the help of an example, explain how variation leads to evolution.

What is persistence of vision? Give one example of persistence of vision.

What are the effects of a force acting on an object?

 Homologous series of alkenes.