WHY IS A FOSSIL FOUND IN MULTIPLE LAYERS OF ROCK (TIME PERIODS) NOT CONSIDERED A RELIABLE INDEX FOSSIL?

Which element is used in photosynthesis found in atmosphere and fixed by bacteria?

Amale bird-of-paradise uses a dance to attract mates in which it flaps its tail feathers on the ground and jumps around a potential female mate. a different male bird-of-paradise does a similar dance but it jumps around the female in the opposite direction. the female bird is only attracted to one style of dance, in one direction. this is an example of speciation.

Nucleus has two lobes; contains granules of lysosomal enzymes; functions in attacking parasitic worms and plays complex roles in inflammatory diseases like allergies and asthma. what blood cells are described?