Answer:
Free fall.
Explanation:
When astronauts sleep in space, they sleep in small cabins or in sleeping bags that are attached to the wall or ceiling of the station. Everything is weightless as there’s no gravity in space. So while sleeping there is a chance of floating around and bumping into things. Astronauts use sleeping bags that can be tethered to the wall or ceiling to solve this problem. Also the tethered sleeping bags provide a normal sleeping environment to the astronauts as they can feel pressure on their back and head. Their sleeping cabin is well ventilated as they can wake up with breathing trouble as a result of the inhalation of their own exhaled carbon dioxide which formed around their heads as a bubble. They use earplugs and a sleep mask to block the noise and light and can sleep vertically or horizontally. Compared to earth, sleeping is a bit different in space.
They evolved during the Cambrian explosion.
Lysosomes looks like a little particles of circle layer covering, placed within the cell's sac.
Complete Question:
Which of the following might stimulate the cephalic phase of gastric secretion?
A. stomach distention
B. the production of saliva
C. the thought of food
D. the production and secretion of gastrin.
Answer:
C. the thought of food
Explanation:
Gastric secretion usually occurs in three different phases, namely;
- Cephalic
- Gastric
- Intestinal
The thought of food usually stimulate the cephalic phase of gastric secretion in organisms. The presence of lipids or low pH inhibits Gastric secretion during the intestinal phase.
Answer:
It is essentially a broth culture filtrate of the penicillium mould.
Explanation:
- Alexander Fleming invented penicillin an antibiotic in 1928. These have been rated as the most important scientific discovery, being among the first antibiotics to be effective against bacterial infection.
- Penicillin belongs to different families that are selective against a large variety of bacteria.
- In fact, this antibiotic was discovered by fleming and accident in which he left a platter containing staphylococci open and was contaminated by green mould. There was an area of inhibited bacterial growth around the mould from which he inferred that the mould produced a material that inhibited bacterial growth. This was found to be a penicillium mould through further study.
- I assume penicillin is the most significant discovery so far because it was the first antibiotic ever discovered against bacterial infection in the absence of any drug.
