Growth factor signaling can trigger mitosis in cells that are in direct contact with other cells

20. A group of students designed an experiment
to determine the effect of compost on the
germination and growth of plants. The students
set up experimental plots by mixing different
ratios of soil and compost. They planted 20 pea
and 20 melon seeds in each plot and watered each
plot regularly. The students recorded the number
of seeds that germinated, and as the plants grew,
they recorded plant length, number and size of
leaves, and general health observations.

The following observations were recorded.

In all treatments, more pea seeds
germinated than melon seeds.

There was a week of rainy weather at
three weeks.

Melon plants developed a fungal growth at
four weeks.

Melon plants grew longer than pea plants,
but many melon leaves showed signs of
yellowing as the weeks passed.

The students concluded that pea plants grew
better in compost than did melon plants.

Which of the following best addresses the validity
of the conclusion made by the students?

How does cell signaling relate to mitosis?

How do growth factors stimulate cell division?

What is the major effect of growth factors on cell division or mitosis?

Which of the following statements best describes how a growth factor stimulates cell division from outside a cell?