Answer:Four spheres of earth are:1)Lithosphere(land) 2)Hydrosphere(water) 3)Biosphere(living things) 4)Atmosphere(air).
Energy and matter flow through Earth's four spheres.Energy flows through the atmosphere and hydrosphere mostly by convection.The continuous cycling of matter and energy through earth's system makes life on earth possible .Others are driven by energy from the sun.
Explanation:
Oncogenes result from turning on, or activating proto oncogenes. Proto oncogenes are genes that code for positive cell cycle regulators, so proto oncogenes code for proteins that turn on cell division. Proto oncogenes are normal genes, but when they are mutated, they become oncogenes. Oncogenes are expressed too much, which makes them turn on cell division too much, which is cancer.
The main food sources of the birds( the plentiful recourses within the environment occupied by the species)
Answer:
implantation – the process by which the zygote attaches to the uterine wall.
Answer:
returns to the left heart, completing the pulmonary cycle
Explanation: