"The number of growth rings" is by far the best indicator of the age of a woody plant, although it should be noted that there are other ways of indicating age.
Secretion of human chorionic gonadotropin [HCG] only occur during pregnancy in the placenta. The concentration of this hormone increase rapidly during the first three months of pregnancy; the amount in the blood stream doubles every two to three days as the development of the placenta and embryo progress. The hormone reaches its maximum concentration peak around the sixth week of pregnancy and after this, its concentration decline.
Answer:
Organelles are specialized structures that perform various jobs inside cells. The term literally means “little organs.” In the same way organs, such as the heart, liver, stomach, and kidneys, serve specific functions to keep an organism alive, organelles serve specific functions to keep a cell alive.
Explanation:
<h2>Energy </h2>
Explanation:
Energy flows in only one direction through an ecosystem
- The Sun supports most of Earth's ecosystems
- Plants create chemical energy from abiotic factors that include solar energy and chemosynthesizing bacteria create usable chemical energy from unusable chemical energy
- The food energy created by producers is passed to consumers, scavengers, and decomposers
- Energy flows through an ecosystem in only one direction, it is passed from organisms at one trophic level or energy level to organisms in the next trophic level
- Most of the energy at a trophic level – about 90% – is used at that trophic level and organisms need it for growth, locomotion, heating themselves, and reproduction
- So animals at the second trophic level have only about 10% as much energy available to them as do organisms at the first trophic level
- Animals at the third level have only 10% as much available to them as those at the second level
