What is the reason given for holding off
on the new techniques for extracting the
oil?

Many companies are afraid to switch to new forms of oil extraction because they can either cost more or don't see in fixing the "Unbroken"

Explanation:

Most of this comes from a deep seated hatred of change in the human mind but also poses an economic scare of whether or no said companies will still maintain their profit margins.

volcanoes (an event in the geosphere) release a large amount of particulate matter into the atmosphere. these particles serve as nuclei for the formation of water droplets (hydrosphere). rainfall (hydrosphere) often increases following an eruption, stimulating plant growth (biosphere).

the level of progesterone is low at the pre-ovulatory phase of the cycle but it gradually increases and the levels are high at the luteal phase. if pregnancy occurs, the level of progesterone will be high throughout the pregnancy.

if egg is fertilized and the mother gets pregnant, progesterone starts preparing the uterus for the implantation. it starts building up the lining of uterus and make it hostile of the period of pregnancy.