The apple tree receives 1000kJ of light from the Sun, but only uses 500kJ. Of this, only 250kJ are stored in the tree to be transferred through the food chain.

a) Calculate the efficiency of the tree (2)

b) State the ways in which the remaining energy has been transferred out the of the food chain (3)

Match the reproductive structures based on their function and the system to which they belong. egg ovary sperm vas deferens vagina fallopian tube testis urethra

According to the rna world hypothesis, rna acted as the genetic material and catalyzed reactions in ancient cells. what conclusion can you draw from this?               a.  this implies that dna and proteins aren't essential in cells today.    b.  this implies that rna can catalyze any chemical reaction that enzymes catalyze.    c.  this implies that if a cell has a problem with its dna, its rna can compensate for the damaged dna.    d.  this implies that dna and proteins evolved after rna.

What do scientific models predict will happen to earth's temperature if current trends continue unmitigated? a. earth will heat and cool in a natural cycle b. earth will heat up and then return to an ice age c. earth will continue to warm at a rate of 0.25 c per decade d. earth will start to cool at a rate of 0.25 c per decade appex