Question

1. the physical sites at which crossing over occurs are the....

A. chiasmata

B. Centrioles

C. Centrosomes

D. tetrads.

2. what is the name for the call structure at the poles" of the cell that spindles fibers attach too?

A. chromatin

B. Centromere

C. Centriole

D. Sister chromatid

3. Explain how we know, the tongue rolling in not inherited in a simple dominant/recessive way and may not be inherited at all. ?

4. A trait is considered multifactorial if it is ........... and influenced by the environment.

Answer 1

1. A-chiasmata and D- tetrads
Chiasmata is X shaped structure present below the brain where two optic nerves cross over each other.
tetrads is a pair of chromosomes which consists four chromatids. the chromosomes exchange genetic material by process of crossing over

2. B - centromere
Long protein fibres called microtubules extend from the centrioles and attach to the centromere and develop into spindle fibres.

3. Tongue rolling is considered as a mendilian trait by a leading geneticist Alfred Sturtevant. It means that it was inherited as a recessive genes specifically from one of the parents. recessive genes means that they can skip a generation and carried to the later generation.

4. A trait is said to be multifactorial if it is influenced by multiple genes and also environmental factors.
Multifactorial means that many factors including genetic and environmental changes are involved in traits.