(i) A group of flowers is called an inflorescence. e.g sunflower.
(ii)The sunflower is not a single flower. It is a group of flower clustered together.
(iii) Tidax procumbens also an inflorescence.

Silicon

When an object travels is a circular path (ie. the initial and positions are same).

An object moving in uniform circular motion is moving around the perimeter of the circle with a constant speed. While the speed of object is constant, its velocity is changing, Ex: Merry-go-round, roller coaster, planets orbiting the sun.

i) Chemical formula is a symbolic representation of one molecule of an element or a compound
ii) It provides information about the elements present in a molecule and the number of atoms of each element.
Significance:
The types of atoms and the number of each types of atoms in one molecule of substance can be known by chemical formula.

In climbers, the leaf of plant would be modified into elongated structure to help the plants climb efficiently is known as tendril.

Insects, birds, animals, wind and water are the agents of pollination.

Density of gold is 19,300 kg/m³

Astronomical unit and light year.

Area, Volume, Speed, Electric charge and Density.

John Dalton proposed the atomic theory in the year 1808.
(i) He proposed that matter consists of very small particles which he named as atoms.
(ii) An atom is smallest indivisible particle, it is spherical in shape.
(iii) His theory does not propose anything about the positive and negative charges of an atom.

(i) Place the irregular object on a graph sheet and draw its outline. Then remove the object
(ii) To find the area enclosed by the outline count the number of small squares.
(iii) If more than half-a-square is inside the boundary, count it as one otherwise neglect it.
(iv) The area of each small square is 1sq. mm.
(v) Area of the irregular object = No. of squares x 1 sq.mm.

Properties of metalloids :
(i) Metalloids exhibit the properties of both metals and non-metals.
(ii) Unusually they look like metals but behave largely like non-metals,
(iii) They can form alloys like metals.

i) Take a measuring cylinder and pour some water into it.
ii) Note down the volume of water from the readings of the measuring cylinder. Take it as V₁.
iii) Now take a small stone and tie it with a thread.
iv) Immerse the stone inside the water by holding the thread.
v) The stone should not touch the walls of the measuring cylinder.
vi) Note down the volume of water and take it to be V₂
vii) The volume of the stone is equal to the raise in the volume of water.
viii) Volume of stone = V₂ - V₁

(i) Yes, an atom of an element has no electron will have the mass.
(ii) (Atomic mass, only depends on the mrmber of protons and the number of neutrons inside the nucleus. It is independent of number of electrons.)
(iii) Atom can exist with out electron and becomes a cation.
Ex: 
1) Hydrogen atoms (Z = 1) has only one electrons.
2) It loses one electron and becomes H⁺ ion
3) H → H⁺ + 1e^-
  (atom)    (Ion)

When solid is heated, the particles gain energy and vibrate vigorously. The particles move slightly further apart from one another.
Hence, the volume increases due to the greater distance between the particles. But the size of the particles remains the same.

Mangrove plants are found in swampy regions where there is water logging and oxygen available for roots will be less. The breathing roots grow above the soil and have pores for gaseous exchange. This helps the roots to get more oxygen with the help of breathing roots

Hydrogen is considered as an element because,
(i) Hydrogen cannot be broken into new substance by ordinary physical or chemical means. (i.e) by applying heat, light.
(ii) Hydrogen has one kind of atoms.

When air inside the hot air balloon is heated with a burner, it expands. The expansion causes the density of the air inside the balloon to decrease. Hence, the air inside the balloon has a lower density that the air outside of the balloon. This difference is density allows the hot-air balloon to float.

If either speed or direction changes, then the velocity is non uniform. Eg. a train starting and moving out of the station.

Density = Mass / Volume
Hence, Volume = Mass / Density
\(=3000 / 8900=30 / 89 \\ =0.34 \mathrm{~m}^{3}\)

Density of cylinder \(=\frac { mass \ of \ cylinder }{ volume \ of \ cylinder }\)
\(=\frac{280}{4}=70 \mathrm{~kg} / \mathrm{m}^{3}\)