The DNA in some lung cells was damaged by the carcinogenic compounds in tobacco and apoptosis was initiated. Which of the following is the best way for the damaged lung cells to send a message to their neighboring cells that they need to increase the production of DNA repair enzymes or start apoptosis as well? A) They should send signaling molecules into the bloodstream.
B) They should send signaling molecules through the gap junctions.
C) They should send signaling molecules across a small extracellular space.
D) They should send signaling molecules by secreting them into the local environment.

Which group of chordates does  notpossess true backbones?                 a.  birds      b.  frogs and toads      c.  lampreys      d.  crocodilians

Amutagen is 1: a living thing that has undergone a mutation. 2: an agent that causes a mutation in dna. 3: a mutation that has affected one gene. 4: a chemical that can poison living cells.

Recent research by marine biologists suggests that bottlenose dolphins have names for themselves. scientists played sounds they had identified as the names of particular dolphins, putting them through a synthesizer so that they did not sound like the voices of particular dolphins. the researchers found that dolphins would respond to the names of other dolphins that they were related to or associated with, but they ignored the names of strangers. this discovery suggests a much greater degree of self-awareness in aquatic mammals than was previously suspected. if this research holds up, what does it suggest about dolphins?