What is thought to be the correct sequence of these events, from earliest to most recent, in the evolution of life on Earth?

1.  origin of mitochondria

2.  origin of multicellular eukaryotes

3.  origin of chloroplasts

4.  origin of cyanobacteria

5.  origin of fungal-plant symbioses

#Question id: 7764

#Unit 5. Developmental Biology

Cellular senescence may have evolved to protect organisms against cancer. Instead of dividing out of control, the cells die. Cellular senescence appears to be regulated by several tumor suppressor genes, especially p53.what is the most appropriate reason behind this,

1) Transcription factor p53 is thought to suppress tumorigenesis by causing cell arrest and senescence in response to short telomeres, DNA damage, and viral or external signals to divide

2) This factor can stop the cell cycle, cause cellular senescence in rapidly dividing cells, instruct genes to initiate cellular apoptosis, and activate DNA repair enzymes.

3) Induction of apoptosis or cellular senescence by p53 always beneficial.

#Question id: 10408

#Unit 6. System Physiology – Plant

#Question id: 15708

#Unit 12. Applied Biology

#Question id: 787

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following statement is INCORRECT with respect to the structure of DNA?

#Question id: 16476

#Unit 12. Applied Biology