Which one of the following plants has unisexual flowers?
- A.Papaya
- B.Hibiscus
- C.Mustard
- D.Sunflower
Correct answer
Explanation
The correct answer is A, Papaya. Papaya bears unisexual flowers: a flower has either stamens or a pistil, and male and female flowers usually grow on separate plants.
A unisexual flower carries only one set of reproductive organs, either the stamens (male) or the carpels (female). Papaya is mostly dioecious, so farmers keep a few male plants among many female plants to ensure pollination and fruit. Other common plants with unisexual flowers are maize, cucumber, watermelon and date palm. A bisexual flower, by contrast, has both stamens and a pistil in the same flower.
B is wrong because the hibiscus flower is bisexual, with stamens around a long style in the same flower.
C is wrong because the mustard flower is bisexual, with six stamens and a pistil.
D is wrong because the sunflower head is made of many small florets, and its disc florets are bisexual.
Exam tip: unisexual flowers: papaya, maize, cucumber, watermelon, date palm; bisexual: hibiscus, mustard, pea, rose.
Practice Questions
View allWhich one of the following is not true for anodizing process?
- A.It makes aluminium corrosion resistant.
- B.Metals like aluminium, titanium and magnesium can be anodized.
- C.Clean aluminium article is the anode and oxygen gas is evolved at the cathode.
- D.It is used in aircraft industry.
Show answer
In anodizing the clean aluminium article is indeed the anode, but oxygen is released at the anode, not at the cathode; hydrogen is released at the cathode.
Read the full explanation →Which one of the following statements is not correct?
- A.The response of the ear to sound of increasing intensity is approximately logarithmic.
- B.The sensitivity of the human ear does not vary with the frequency of the sound.
- C.When two or more waves traverse the same medium, the displacement of any element of the medium is the algebraic sum of the displacements due to each wave.
- D.Longitudinal waves can travel in all media—solids, liquids and gases.
Show answer
The statement that the sensitivity of the human ear does not vary with frequency is false, because the ear is far more sensitive to some frequencies than to others.
Read the full explanation →Kwashiorkor disease in children is caused by
- A.sufficient carbohydrates but less fats in diet
- B.sufficient carbohydrates and fats but deficient proteins in diet
- C.sufficient vitamins but deficient fats in diet
- D.sufficient fats but deficient vitamins in diet
Show answer
Kwashiorkor is a disease of protein deficiency in a child who still gets enough calories. It usually appears when a child is weaned from breast milk onto a starchy diet with little protein.
Read the full explanation →Which one of the following is the correct order of pH for the given substances?
- A.Coffee < Lemon juice < Milk of magnesia < Blood
- B.Milk of magnesia < Blood < Coffee < Lemon juice
- C.Lemon juice < Blood < Coffee < Milk of magnesia
- D.Lemon juice < Coffee < Blood < Milk of magnesia
Show answer
Arranged from most acidic to most basic, the four substances fall in exactly this order. Lemon juice, rich in citric acid, has a pH of about 2 to 2.5.
Read the full explanation →Which one of the following diseases may be caused by the deficiency of vitamin C?
- A.Rickets
- B.Rabies
- C.Hepatitis
- D.Scurvy
Show answer
Scurvy is caused by a lack of vitamin C, or ascorbic acid, which the body needs to make collagen, the protein that holds skin, gums and blood vessels together.
Read the full explanation →