Enter Title

CHEMISTRY

100

I help things burn, but I’m not a flame. I’m in the air and needed for life—what am I?

Oxygen

200

I start the reaction; I'm there first without me nothing works 

reactant

300

I burn so bright, you shouldn't stare, I join with oxygen

magnesium

400

We break apart, We join together,
But we never leave—Not now, not ever.We move around,
We change our places,
But you will always
Find the same faces.

Atoms

BIOLOGY

100

I have a nucleus, cytoplasm too plants and animals both have me who am I

Cell

200

You can find me only in plants, I give them their definite shape. Who am I 

Cell wall.

300

I help you grow big and strong,
I give you energy all day long.
You take me in when you eat your food,
Without me, your body wouldn’t be in the mood.
Which life process am I?

nutrition

400

I am tiny, seen with lens I can make a yoghurt and sometimes illness

microorganisms

bacteria

PHYSICS

100

I only work when things touch tight,
I slow you down, though you may fight.
When you slide or rub, I come alive,
What force helps you stop and survive?

friction

200

You push the ground; it pushes back,
Without this force you’d lose your track.
I act in pairs and need contact too,
What force am I that helps you move?

reaction force 

300

I help lights shine bright at night,
I help you run with all your might.
I cannot be seen, but I’m always there,
I make things move everywhere.
What am I?

energy

400

I travel as waves you cannot see,
I help you hear a friend call “me!”
I need a medium to move around,
What am I, known by this name and sound?

sound