Question

Which one dental formula represents a heterodont placental draught and tough animal?
1. 3142/3142
2. 3131/3131
3. 2033/2033
4. 3143/3143

Read as Incisor, Canine, Premolar and Molar left to right.

Eliminate options with justification
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Answer 1

Answer:

3143/3143 is the dental formula which represents a heterodont placental draught and tough animal.

Explanation:

Dental formula (3143/3143)×2 = 44 belong to draught animal horse. The animal possess highest number of teeth among heterodont placental animal. Rest three dental formula belong to cat, dog and rabbit.

"HOPE IT HELPS"

Answer 2

Correct Question

Which one dental formula represents a heterodont placental draught and tough animal?

1. 3142/3143

2. 3131/3121

3. 2033/1023

4. 3143/3143

Answer :-

Correct Option :

4⟩ 3143/3143

Statement - 3143/3143 is the dental formula represents a heterodont placental draught and tough animal.

Step-by-step Explanation :

The number and arrangement of teeth in the jaw is represented bye dental formula, both teeth of right and left of each jaw is same.

The dental formula :-

$\sf{Dental \: formula = \dfrac{Number \: of \: teeth \: in \: one \: half \: of \: upper \: jaw}{Number \: of \: teeth \: in \: one \: half \: of \: lower \: jaw} \times 2} \\ \\ \sf{ = \dfrac{I + C + Pm + M}{I + C + Pm + M} \times 2} \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \:$

Here,

• I = The number of incisors.
• C = The number of canines.
• Pm = The number of premolars.
• M = The number of molars.

$\:$

Solution :

$\sf{1. \: \: \: \: \dfrac{3 \: 1 \: 4 \: 2}{3 \: 1 \: 4 \: 3}}$

Ans) Not a correct Option.

Reason) This dental formula is of a Dog.

ㅤㅤㅤㅤ_________________________

$\sf{2. \: \: \: \: \dfrac{3 \: 1 \: 3 \: 1}{3 \: 1 \: 2 \: 1}}$

Ans) Not a correct Option.

Reason) This dental formula is of a Cat.

ㅤㅤㅤㅤ_________________________

$\sf{3. \: \: \: \: \dfrac{2 \: 0 \: 3 \: 3}{1 \: 0 \: 2 \: 3}}$

Ans) Not a correct Option.

Reason) This dental formula is of a rabbit.

ㅤㅤㅤㅤ_________________________

$\sf{4. \: \: \: \: \: \dfrac{3 \: 1 \: 4 \: 3}{3 \: 1 \: 4 \: 3}}$

Ans) Is a correct Option.

Reason)

The heterodont placental draught and tough animal has:

Incisors = $\tt{\dfrac{3}{3}}$

Canines = $\tt{\dfrac{1}{1}}$

Premolars = $\tt{\dfrac{4}{4}}$

Molars = $\tt{\dfrac{3}{3}}$

So as by, The dental formula, no. of teeth :-

$\sf{ \longrightarrow \: \dfrac{3 \: 1 \: 4 \: 3}{3 \: 1 \: 4 \: 3} \times 2}$

$\sf{ \longrightarrow \: 44 \: teeth}$

Things to remember

• $\boxed{\sf{Dental \: formula = \dfrac{Number \: of \: teeth \: in \: one \: half \: of \: upper \: jaw}{Number \: of \: teeth \: in \: one \: half \: of \: lower \: jaw} \times 2}}$