Answer:
A phosphate backbone is the portion of the DNA double helix that provides structural support to the molecule. DNA consists of two strands that wind around each other like a twisted ladder. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups.
Point source means: the pollution that comes from a single point (examples)
Sewage pipes releasing sewage into a ditch
Smokestack style factory chimneys
Oil pipes
Pollution which is caused by rain fall or snow melting into the ground. As the runoff moves, it picks up and carries away natural and human made pollutants, Finally reaching a lake, river, ocean, groundwater.
All organisms are grouped into five kingdoms. Those are Monera, Protoctista, Fungi, Plantae and Animalia. The division is made based on 3 criteria. Those are cellular organization, arrangement of cells, and type of nutrition. Cellular organization is whether they are eukaryotic or prokaryotic. Cell arrangement is whether they are unicellular, multicellular, with or without true tissue differentiation etc. Type of nutrition is whether they are autotrophic or heterotrophic. Kingdom Protoctista includes algae, protozoans, oomycota and slime moulds.
If it's two different kinds of birds it's called competition.
