Plant Growth and Mineral Nutrition — BIOLOGY STD 12 Science — Question

What is humus? Mention its properties.

What does an interaction between pollen grain and its compatible stigma result in, after pollination? List two steps in sequence that follow after the process.

Discuss briefly the following:

1. Greenhouse gases.
2. Catalytic converter.
3. Ultraviolet B.

Why do animals need to maintain homeostasis?

While holding a tea cup Mr. Kothari’s hands rattle. Which disorder he may be suffering from and what is the reason for this?

Mrs. Peter and Mrs. James had babies at the same hospital. Mrs. Peter took home a girl, Nancy and Mrs. James received a boy, Richard. However, Mrs. James was certain she gave birth to a girl and brought suit against the hospital. Blood tests showed that Mr. James was type O, Mrs. James was type AB and Mr. and Mrs. Peter were both type B. Nancy was type A and Richard was type O. List the possible genotypes of each individual and then indicate the correct parents for each child.
Genotypes :

1. Mrs. Peter ____________.
2. Mr. Peter ______________.
3. Nancy _____________.
4. Mrs. James _________________.
5. Mr. James ________________.
6. Richard _______________.
7. Whose baby is Nancy?
8. Whose baby is Richard?

What will be the effect of thyroid gland atrophy on the human body?

Describe the discontinuous synthesis of DNA.

Osmotic Pressure (O.P) and Turgor Pressure (T.P)

A red–eyed heterozygous female fruit fly is crossed with a red–eyed male. Work out all possible genotypes and phenotypes of the progeny. Comment on the pattern of inheritance of eye colour in fruit flies.