Ecosystems — BIOLOGY STD 12 Science — Question

When does ovulation occur?

The immune system of a person is suppressed. In the ELISA test, he was found positive to a pathogen.

1. Name the disease the patient is suffering from.
2. What is the causative organism?
3. Which cells of body are affected by the pathogen?

Who gave the concept of hot spots? What are the major criteria for number of species conserved there?

Refer to the diagram given below and answer the questions that follow.

1. The parasite reproduces in human host by which method?
2. The sexual stages of parasite are referred to as?
3. Where does the fertilisation and development of parasite takes place in mosquito body?
4. What are sporozoites?
5. What is the cause of cycles of fever during malaria?

Write the three critical research areas of biotechnology.

During a visit to Vaishno Devi, Rahul came across a young couple staying in the adjacent room in the hotel. He learnt that the couple had been visiting different temples and performing rituals to get a child. Rahul was astonished and explained to them about ART which he had recently studied in their wrong approach and thanked Rahul.

1. What is ART? What are the various methods included in ART?
2. What are the limitations for which ART is not commonly accepted?
3. Identify the values which Rahul showed.

Fill in the trophic levels (1, 2, 3 and 4) in the boxes provided in the figure.

When did the following appear on the geological history?

1. Invertebrates.
2. Jawless fish.
3. Sea weeds.

What are test tube babies?

Draw a well labelled diagram of mature graafian follicle.