Reproductive Health — BIOLOGY STD 12 Science — Question

Study the schematic representation of evolutionary history of plant forms given below and mention

1. The plant forms ferns and conifers are most related to.
2. The nearest ancestors of flowering plants.
3. The most primitive group of plants.
4. Common ancestry of Psilophyton provides to.
5. The common ancestor of Psilophyton and seed ferns.
6. The common ancestors of mosses and tracheophytes.

'Introducing sex education in school is a good step for providing right information to adolescents'. In context to the statement given above, answer the questions that follow.

1. Which part of the brain controls the sex urge?
2. What are the necessary topics that should be taught in schools, in context of STDs and AIDS.

What is the significance of progestogen oestrogen combination as a contraceptive measure?

1. Draw a neat labelled diagram of a nucleosome.
2. Mention what enables histones to acquire a positive charge.

Explain the sexual deceit found in orchid. ###Why shape, colour and markings of a petal of the Mediterranean orchid flower are similar to those of a female bumble bee? Explain.

Luteal phase of the menstrual cycle is also called the secretory phase. Give reason.

A recombinant DNA is formed when sticky ends of vector DNA and foreign DNA join. Explain how the sticky ends are formed and get joined.

Substantiate with the help of one example that in an ecosystem mutualists:

1. Tend to co-evolve.
2. Are also one of the major causes of biodiversity loss.

Name the category of codons, UGA belongs to. Mention another codon of the same category. Explain their role in protein synthesis.

Compare the two ecological pyramids of biomass given below and explain the situations in which this is possible. Also, construct an ideal pyramid of energy, if 200,000 joules of sunlight is available.