The diagram shows a view of a model glider from above.
The aspect ratio of a wing is the length of the wingspan divided by the length of the chord. The higher the aspect ratio, the more effectively a plane will glide.
The following photographs show four birds.
Which bird would be the most effective glider?
Plants produce sugar through the photosynthesis pathway. The products are stored in parts of plants such as a fruit, bulb or tuber. Which tissue is most likely to transport the dissolved sugar to the storage?
Ebola is one of the most dangerous diseases in the world. The symptoms start two days to three weeks after infection, in the forms of fever, sore throat, muscle pain, and headaches. The current outbreak in West Africa (first case was notified in March 2014) is the largest and the most complex Ebola outbreak since the Ebola disease was first discovered in 1976.
Which of the following statements about the Ebola disease is not correct?
The illness infects humans and non-human primates.
Ebola virus destroys the membrane of the red blood cells.
Fruit bats are natural Ebola disease hosts.
Ebola virus spreads through the bodily fluids of infected people.
Analyze the age structure diagrams of six different representative countries shown in the following figure. The age structure diagrams are typical of many countries in the world. Which diagram shows a rapidly growing country?
Sharks belong to the class of Chondrichthyes (chondrichthyans), which is different from the Osteichthyes or bony fish as their skeleton is cartilaginous. Sharks do not have any protective organs covering over their gills (called an operculum).
Consequently, to breathe, sharks have to ______
Ahmad and Badru are standing at the top of a cliff of height $H$. Both of them, then, throw a ball with the initial speed of $v_0$. Ahmad throws the ball straight down and Badru straight up. The speed of the balls when they hit the ground is $v_A$ and $v_B$ respectively. Neglecting air resistance, which of the following statements is true?
A force $F$ is acting on a mass of $m_1$ resulting in an acceleration of $a_1$. The same force is acting on a different mass of $m_2$ resulting in an acceleration of $a_2=2a_1$.
If $m_1$ and $m_2$ are glued together and the same force $F$ acts on this combination, what is the resulting acceleration?
In an area of a volcano, we can find hot water at the temperature of 300 °C at the depth of 3000 m in fluid phase. The main aspect that causes the water in fluid phase is _______________
Mr Umar, a cattle rancher from Lombok, Nusa Tenggara Barat, Indonesia, is trying to hybridize some cows to improve his cattle quality. In order to know which cow will produce high quality of calves, he has already done a DNA test to the parents and their offspring. The DNA test result can be seen in the pictures above. Match the parents of cows with the right calf!
_________________________________________ and ___________________________________________
The South African Climate Change and Air Quality Intergovernmental Committee monitor air quality using a Regional Pollution Index (RPI). The RPI for a particular pollutant is calculated by:
$$RPI=\frac{\text{pollutant concentration}}{\text{pollution standard level}}\times50$$
| Level | RPI |
| --- | --- |
| low | RPI between 0 and 24 |
| medium | RPI between 25 and 49 |
| high | RPI 50 or higher |
(1 point) Ozone is a pollutant. On a particular day the RPI of ozone was 85. Was the concentration of ozone less than the pollutant’s standard level? ______________________
(2 points) The standard level for the pollutant, nitrogen dioxide, is 0.12 parts per million (ppm) per hour. Scientists monitored the levels of nitrogen dioxide for one hour and determined that the RPI was 25. What was the concentration (ppm per hour) of the nitrogen dioxide? _________________________________
(2.5 points) Power $P$ is defined as a time rate of energy or the work done in a time interval $\Delta t$, $P=W/\Delta t$. There are two engines, A and B, which have a power ratio of 2:1. If engine A does a work of 1000 joule in 200 seconds, the work done by engine B in 300 seconds is ____________________________
