CBSE 12TH BIOLOGY - Online Test
Q1. Which of the following contraceptive method is useful to control STD’s as well as unwanted pregnancy
Answer : Option A
Explaination / Solution:
Condoms are protective covering of penis that do not allow the passage of semen into vagina of female during sexual intercourse. This contracetive prevents the fusion of body fluid of male and female and protect from STDs.
Q2. Interacting members of species live close to each other in following interaction/s:
Answer : Option A
Explaination / Solution:
Individual organisms live together in an ecosystem and depend on one another. In fact, they have many different types of interactions with each other, and many of these interactions are critical for their survival.
Interacting members of species live close to each other in commensalism, predation and parasitism.
Q3. Post erythrocytic part of life cycle of plasmodium is called
Answer : Option D
Explaination / Solution:
The post erythrocytic part of life cycle of plasmodium is called Ross cycle. This cycle is named after the scientist Ronald Ross, who discovered the cycle of malarial causing protozoa, plasmodium.
Q4. Which of the following is structural subunit of DNA?
Answer : Option A
Explaination / Solution:
Consisting of a five-carbon sugar (deoxyribose) a phosphate group and a nitrogenous base, a nucleotide links with another nucleotides in a repeating sequence, forming a very long, continuous strand of DNA.
The nitrogenous base will be one of four types: Guanine(G), Adenine (A), Cytosine (C) or Thymine (T).
Q5. Organism/s living as both producer as well as consumer is/are
Answer : Option A
Explaination / Solution:
Nepenthes (pitcher plant) and Drocera are insectivores plants to compensate their protein requirement. They have green leaves that perform photosynthesis process. So, they act as both producer as well as consumer.
Q6. Main objective of production or use of herbicide resistant genetically modified crops is to
Answer : Option A
Explaination / Solution:
Herbicides are chemicals that kill the herbs that grow with crop plants. Use of herbicides results into accumulation of herbicide in food and water. To overcome this problem herbicide resistant genetically modified crops are used.
Q7. In a wetland the primary factor controlling the environment and the associated plant and animal life will be
Answer : Option A
Explaination / Solution:
The area that is saturated with water is called wetland. In wetland the primary factor controlling the environment and the associated plant and animal life will be water.
Q8. Flower is a modified shoot because
Answer : Option D
Explaination / Solution:
Flower is a modified shoot because it develops in the axils of bracts like axillary shoots. New buds also develop at node inside the axils of bracts of leaves.
Q9. The part of fallopian tube closest to ovary is
Answer : Option B
Explaination / Solution:
Fallopian tube or oviduct of human female is divided into three parts, Infundibulum, ampulla and isthmus. The infundibulum is closet to ovary.
Q10. Each gametes carry
Answer : Option A
Explaination / Solution:
Each gametes carry single set of chromosomes. During gamete formation each pair of alleles separate from each other as reduction division occurs.
