Answer:
The first layer is the crust, a skin of rock covering the planet. The core that Lehman had found was the Earth's inner core. The core that Richard Oldem had discovered turned out to be the Earth's outer core.
Explanation:
Ans.
Steroids are defined as active organic bio-molecules, having four rings with a specific molecular configuration. Steroids play role in two major functions: as hormones or signaling molecules and as structural components of plasma membrane.
Examples of steroid hormones are estrogen, progesterone, and cortisol. Thus, the correct answer is 'option b). they serve as chemical messengers.'
Color, smell/ odor, taste
A.
Endangered species is closer to extinction
Threatened ones are closer to becoming endangered
