Answer:
The four seasons happen because of the tilt of the Earth's axis. At different times of the year, the sun's rays hit different parts of the globe more directly. The angle of the Earth's axis tilts the Northern Hemisphere towards the sun during the summer.
Explanation:
Answer:
Aa
Explanation:
In Punnett Square, you are bringing the letters on the top to the numbered squares, if that makes sense. It is to predict the genotype of offspring.
So square 1, on the left is A, and on the top is A, so it would be AA.
For square 2, on the left is a, and on the top is A, so it would be Aa.
For square 3, on the left is A, and on the top is A, so it is AA.
Square 4, your question, has a on the left, and A on the top, so it is Aa.
Hope it makes sense. You should probably watch a Punnett Square tutorial online or something for a full and more general explanation.
Answer:
C. Oxygen
Explanation:
Most, if not all living things use oxygen in some shape or form. While Helium is the most abundant element, it is asking for living things, in which oxygen is a vital building block in maintaining life. Without oxygen, most animal species and humans would die.
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The physical characteristics that determine the exhistance of organisms in aquatic enrironments relate to its pH (which is whether it's acid, neutral or basic), the water clearance (which refers to the particles diluted in it, the presence of toxic substances, etc), the presence of predators (bio chain) and also if there's enough food for the organisms to live, to reproduce and if the water temperature allows them to subsist or if they need to migrate within a year, due to the natural changes.