Answer:
What type of plants are extinct?
Explanation:
Prehistoric extinctions
Cooksonia.
Archaefructus.
Abies milleri.
Dillhoffia.
Trochodendron nastae.
Araucaria mirabilis.
Araucarioxylon arizonicum.
Sphenophyllum miravallis.
Answer:
3. haploid; diploid
Explanation:
Sperm is male gamete or often called male reproductive cell. During the process of spermatogenesis, reductional division (meiosis) occurs in the spermatocytes and spermatids are formed which further mature to sperms. Thus as a result of meiosis, their chromosome number is reduced to half and thus they become haploid cells. During oogensis, eggs are also formed as a result of meiosis which reduces the chromosome number and so eggs are also haploid.
When during fertilization, these two haploid nucleus of these cells fuse together, they form a diploid zygote.
Answer: When a plant is exposed to light, photons of appropriate wavelength will strike and be absorbed by the pigment-protein complexes arrayed on the thylakoid membranes. When this happens, the energy of the photon is transferred to the pigment molecule, thus causing the pigment to go into an electronically excited state. :)
Explanation:
Answer:
Feedback inhibition and allosteric regulation.
Explanation:
Answer:
By using the secretion of insulin and glucagon.
Explanation:
When the level of glucose in blood is high the pancreas secretes insulin that sends a negative feedback signal to the liver to absorb glucose. Synthesis of fats is initiated, glucose transported to the muscles and adipocytes for storage through glycogenolysis.
When the levels of glucose are too low in the blood, the pancreas secretes glucagon to initiate the breakdown of glycogen by the liver.
