Which among the following statements about tetrad is true? 1) Two chromosome
2) Four chromatid
3) Two kinetochore
4) Four centromere
5) Formed in zygotene and clearly appears in pachytene
6) Formed by the formation of synaptonemal complex

A. All are correct
B. 1,2,5,6 are correct
C. 1,2,3,5 are correct
D. 1,2,3,4,5 are correct

Groups of organisms with low biotic potential, such as gray whales, that produce at most one offspring every other year a) are r-selected b) are k-selected c) are not subject to density-dependent limiting factors d) show the initial stages of the extinction process e) have escaped from the processes of natural selection and adaptation

What is the difference between the conducting zone and the respiratory zone of the respiratory system? the conducting zone is a series of cavities and tubes that move air to the respiratory zone where gases exchange with the bloodstream. the conducting zone exchanges gases between the lungs and the alveoli and the respiratory zone is a series of cavities and tubes that move air to the conducting zone. the conducting zone moves oxygen into the cells and the respiratory zone takes carbon dioxide away from the cells. the conducting zone moves oxygen into the bloodstream and the respiratory zone takes carbon dioxide away from the bloodstream.

Suppose you could go back in time to interview henri becquerel on the day he discovered radioactivity. from his perspective, write an account of the discovery.