The female gametophyte is a structure called an
embryo sac, while the male gametophyte is a
structure called a pollen grain. When pollen attaches to the stigma of
a flower, one of the sperm cells fertilizes an egg cell, producing a
zygote. Another sperm cell fertilizes the polar
nuclei, forming a
endosperm. The
will eventually develop into the sporophyte.

Asolution of an enzyme and a substrate was placed in a water bath and the temperature of the reaction was raised gradually. the graph shown was plotted at the end of the experiment. what can be concluded from the graph? a) temperature has no effect on the activity of the enzyme. b) the effect of temperature on the enzyme is unpredictable. c) the enzyme shows increased activity up to a certain temperature. d) the activity of the enzyme is inversely proportional to the temperature.

Pulmonary arteries carry highly oxygenated blood. true or false?

What kinds of molecules can pass through the cell membrane without any problem?