Which of the following can be categorized as a primary activity?

Plants in the tundra biomes have had to adapt to live long periods of time without a. cool temperatures b. sunlight c. oxygen d. water

One of the brightest comets of the 20th century was comet hyakutake, which passed close to the sun in early 1996. the orbital period of this comet is estimated to be about 30,000 years. find the semi-major axis of this comet’s orbit. compare it to the average sun-pluto distance and to the distance to alpha centauri, the nearest star to the sun, which is 4.3 light-years distant.

The ozone hole is at its biggest each year in the ? hemisphere in the ? season.