Can a plant reproduce without another plant involved? Does the rock cycle have a beginning? What are two ways carbon dioxide is released into the atmosphere?

Yes, a plant can reproduce without another plant involved.

No, there is no beginning of rock cycle.

Two ways in which carbon dioxide is released into the atmosphere are burning of fossil fuels such as petrol and coal etc and respiration process.

Explanation:

This type of reproduction occurs in non seed bearing plants such as ferns and mosses etc. These plants reproduce by the formation of spores. Spore formation is a type of asexual reproduction in which only one plant is involved. In cellular respiration, glucose molecule is broken down and energy is released with carbon dioxide gas. Fossil fuels are also responsible for the emission of carbon dioxide gas after burning in vehicles and industries.

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."