When the trading of equivalent sections of DNA between homologous chromosomes occurs during crossing over, it is called: A. reciprocal exchange.
B. chromosomal exchange.
C. allele exchange.
D. similar crossing-over.

Suggest why placing wheels under a heavy box reduces the neccessary force required to push it along at a constant speed.

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?

Identify the area on the image where the force of attraction is the strongest.